You are logged in as a guest. ( )John Deere 8010/8020 Jump to page: Now viewing page 1 50 messages per page::-Message formatPosted 11/4/2015 11:35 (#4876495) Subject: John Deere 8010/8020Does anyone know where any of those tractors are?Posted 11/4/2015 11:39 (#4876505 - in reply to #4876495) Subject: RE: John Deere 8010/8020Yes, there's one on the cover of the November issue of Green Magazine.
The far-fetched experimental tractors the engineer's fertile imaginations conceived, and their talented hands assembled, were to change the agscape for all time. Many, many experimental tractors had been produced up until the time line of this article. Most were prototypes; the forerunner of an actual production unit. Sep 10, 2018 - only John Deere 8010 in existence is at the Keller Tractor Museum.
![Keller experimental john deere parts Keller experimental john deere parts](/uploads/1/2/5/4/125451747/155766411.jpg)
The photo was taken at Half Century of Progress. There were a couple of other ones there also. Edited by nosoup4u 11/4/2015 11:40Posted 11/4/2015 13:05 (#4876628 - in reply to #4876495) Subject: RE: John Deere 8010/8020Are you looking to buy one or what?Posted 11/4/2015 13:53 (#4876688 - in reply to #4876495) Subject: RE: John Deere 8010/8020Sunburst MontanaStart doing a search the net. Try asking over at YTmag on the JD forum. Neighbor just gave me an air cleaner that came off a 8020 that used to be there. Closest I will get to owning one.Posted 11/4/2015 13:56 (#4876692 - in reply to #4876688) Subject: RE: John Deere 8010/8020A guy I know has a registry of them. I think he has about 75 of the 100 built recorded.
Current prices are around 100K.Posted 11/4/2015 14:06 (#4876701 - in reply to #4876628) Subject: RE: John Deere 8010/8020I was looking to buy onePosted 11/4/2015 15:06 (#4876758 - in reply to #4876495) Subject: RE: John Deere 8010/8020There is a serious collector at Forest Junction, Wi who has an 8010. Weren't they supposed to have been recalled and converted to 8020's?Posted 11/4/2015 15:28 (#4876774 - in reply to #4876758) Subject: RE: John Deere 8010/8020Somehow his got missed.Posted 11/4/2015 18:03 (#4876997 - in reply to #4876758) Subject: RE: John Deere 8010/8020The Jan-Feb 2008 issue of Two Cylinder magazine says based on the Waterloo Production Log in their possession that 100 8010 were really built. It says that in 1963 they were recalled for a chronic transmission cooling problem and some other updates. The records show only 77 tractors were returned and updated to 8020. They appear to have some ideas but didn't show them.My guesses are that some hadn't been shipped, and some had been shipped but not sold, and that some owners were unwilling to turn loose of them for a year (recalled in 1963 returned in 1964 ), Likely some owners didn't think the problem was significant in their use.
Then some may have been shipped nearly halfway around the world and shipping back was expensive for the owners, and maybe if they had real problems some may have burned by the time of the recall and so had been scrapped.Gerald J.Posted 11/4/2015 19:03 (#4877125 - in reply to #4876997) Subject: RE: John Deere 8010/8020Gerald is correct some hadn't been shipped yet. Some were still in stock in 1965.Posted 11/4/2015 19:31 (#4877198 - in reply to #4876758) Subject: RE: John Deere 8010/8020Freedom, WIYes, the Keller brothers. They have the only remaining 8010 and I don't think it is just any 8010, I believe it is an experimental model more or less. #1 serial number I thought, not sure if true or not though.Posted 11/4/2015 21:57 (#4877661 - in reply to #4877198) Subject: RE: John Deere 8010/8020I think that the Kellers are actually a Father/Son.Walter/Bruce.Posted 11/5/2015 05:22 (#4877875 - in reply to #4876495) Subject: RE: John Deere 8010/8020Seaforth, OntarioI know of three within 6 miles of me. Would love to have one.
A neighbor of mine once had three himself.Jump to page: Now viewing page 1 50 messages per pageJump to forum:.
Contents.Dain All-Wheel Drive The Dain All-Wheel Drive was the first tractor produced by John Deere and had only a single rear wheel. In 1911, Deere purchased the Dain Manufacturing Company of Ottumwa, Iowa.
The next year, Deere decided to design its own tractor, and Dain founder Joseph Dain Sr., was directed to design that tractor. After several prototypes, the design was finalized in 1917, and 100 production units were ordered. By 1919 when that production run was complete, Deere had purchased the Waterloo Boy company. Although the Dain AWD was ahead of its time, with features such as a shift-on-the-fly transmission, Deere halted production in late 1919, partly because the cost of the Dain tractor was double that of the Waterloo Boy, and partly because of the death of Dain Sr.Waterloo Boy.
Waterloo Boy tractorThe predecessor of Waterloo Boy came about in 1892. It was made by thresherman John Froelich. It is called the Froelich tractor.
Scale Models of Dyersville, Iowa made a 1/16 scale toy of this tractor. In March 1918 Deere & Company decided to continue its foray into the tractor business by purchasing the which manufactured the popular Waterloo Boy tractor at its facilities in.Deere & Company continued to sell tractors under the Waterloo Boy name until 1923.Model D (Spoker Model D). John Deere model D tractorDespite a rather severe farm economy depression at the time, Deere management decided to build a Model D prototype in 1923, designed by Muir L. Frey (father of Ford Mustang designer ). The Deere Model D was produced from March 1, 1923 to July 3, 1953, the longest production span of all the John Deere tractors. Over 160,000 were made.The first Model D rode on steel wheels with a 6.5 in × 7 in (170 mm × 180 mm) (later 6.75 in × 7 in (171 mm × 178 mm)) two-cylinder hand-cranked engine rated 15–27 hp (11–20 kW). It was not, however, the first tractor to bear the Deere name - as a number of Deere experimental tractors, and the John Deere Dain 'All Wheel Drive' tractor (of which approximately 100 were produced during 1918 and 1919) had all carried the Deere name before the D.By 1925, the company realized the standard Model D did not meet customers' needs for industrial applications.
Steel wheels were not suitable for hard surfaces, and the gearing was too slow for safe road speeds. Solid rubber tires were added, and engineers fitted a 28-tooth sprocket to the final drive, giving a road speed of 4 mph (6.4 km/h). The company replaced the 465 (7.62 ) two-cylinder engine with a 501 (8.21 ).
In 1926, Deere advertised the model as the 'John Deere Industrial Tractor' with 40 × b inch rear wheels and 24 in × 3.5 in (610 mm × 89 mm) fronts with solid tires. This became known as the 'DI'.
Options also included wheel weights. GP tractor On June 20, 1928, the model designation was changed from 'C' to 'GP' to avoid confusion with the 'D' when dealers were phoning in orders to the factory. 'GP' stands for 'General Purpose'. This new model GP had the same horsepower, engine displacement, weight and three-speed transmission as the model C. The GP's first serial number was 200211. John Deere model M TractorAfter the models A and B got new styling, both tractors were given six-speed transmissions in late 1940.
The A was 29 hp out of a 321 CID engine while the smaller B was both 18 and 23 hp reflecting the earlier and later updates between 1938 and 46. The 14.84 model H was given the Dreyfuss look from the time it was introduced in 1938. The H broke a fuel economy record when it was tested in Nebraska. This tractor also had three variations that came out in 1940-'41. The H tractor was 14.84 horsepower out of a 90 CID engine and had a three-speed transmission.
Model AW (1947-52, late styled) in original condition, museum, NSW AustraliaIn 1939, the restyled model D appeared. The D was a 42 hp tractor, and weighed 5,300 pounds. Options available on this tractor included electric lighting and starting.
In August 1940 John Deere introduced the new model LA which was followed by the model LI. The LA had a 77 CID engine with 14 belt horsepower. The John Deere G tractor was restyled in 1941 but did not start to roll off the assembly line until early 1942. Like the smaller A/B tractors the G model also had the 6-speed transmission, but also featured electric lights and electric start.In 1947, John Deere opened a new tractor factory in, built to produce the John Deere M. The M was created to address the increasing demand for small tractors and compete with the increasingly popular and the smaller models.
The M was the first Deere tractor to use a vertical two-cylinder engine, with a square bore and stroke of 4.0 × 4.0 inches (100.5cuin) with a high row crop.1949–1959: diesels and post World War II production. John Deere Model 430S Circa 1960After years of testing, John Deere released its first proper tractor in 1949, the Model R. The R was also the first Deere tractor with a 'live' independent equipped with its own clutch.
The R also incorporated live hydraulics. PowrTrol, as it was known, provided the operator the ability to lift equipment by the pull of a lever. A pump powered by the PTO clutch provided 1800 PSI of hydraulic pressure to a lever controlled valve. At 45 hp at the drawbar and 50 hp at the belt, it was the most fuel-efficient tractor available at the time, and this combination of features resulted in over 21,000 being built. The model R had a shipping weight of 7,670 lb.
The R was equipped with two engines. The primary plant is a two-cylinder, four-stroke, naturally aspirated 416 cubic inch (5.75 X 8 bore and stroke) direct injected diesel engine with a 16:1 compression ratio. The starting motor is also a Deere two-cylinder, 26 cubic-inch horizontally opposed gasoline engine. The starting or 'pony' engine is electrically started by a six-volt electrical system, and is used to crank the diesel.
Testing results with various electrical starting systems for the diesel proved to be too bulky requiring a 24- or 32-volt system. The design of the pony start Rs allowed for hot exhaust gasses to preheat the intake air for the diesel and a common liquid cooling system allowed the pony engine to warm the diesel block and head. This provided sufficient cold weather starting aids for the diesel that it would reliably run in sub zero conditions.
The R did have several teething problems as this was Deere's first production diesel tractor. Available as a standard tractor only, it did not have an adjustable front axle, nor did it have a three-point hitch. The engine was mainly an up-scaled gasoline engine from the Model D. The use of a cooling system and the lack of a three-point bearing crankshaft proved inadequate for diesel compression ratios. The R was prone to overheating and cracking the cylinder head.
The lack of a center main bearing in the crankshaft allowed the shaft to flex when used as a stationary powerplant on the belt; this would lead to its failure. The live PTO was directed through (2) 45° bevel gears that proved too small to durably transmit the full torque of the engine.
The tractor was fully serviceable at pulling larger equipment efficiently on large acre wheatland farms.During the 1950s, the R saw a series of upgrades in the models 80, 820 and 830. The 80 was produced for two years and 3,500 were produced. It had new features, including and dual hydraulics. It developed 68 hp and weighed 8,100 pounds. The 80 also corrected the other design flaws within the R such as using a water pump and pressure radiator cap and the addition of a center crankshaft main bearing.The 820 and 830 were similar overall, but also differed in their exteriors, fuel tank designs and color schemes.
The 820, a larger version of the 720 and the 720, was basically the same as the 70, except for the model number and that the sides of the hood are painted JD yellow. The 720 was upgraded to the 730 for 1959. The 730 featured more contoured bodywork than the 720 and came with more ergonomic features for the operator. Although the 730 had a short production run it became one of John Deere's most popular models. The 730 also featured power steering and 24-volt electric starter motor instead of the V4 pony start engine. The 730 was available in diesel, gasoline and LPG as well as in row crop tricycle, row crop wide front, standard tread and hi crop wide front formats.
The 730 is very popular with tractor pulling enthusiasts because of its weight, power and slow speed. Plus its good looks have become popular with tractor restorers. The 730 was a 59 hp tractor at the belt and 54 at the drawbar.After making more than 1 1⁄4 million two-cylinder tractors, John Deere switched to four- and six-cylinder engines. Announcement of the change came after seven years of development and forty million dollars in retooling.In October 1959 the company showcased a new large 215 hp 4WD, called the 8010, on the Robert Ottilie Seed Farm north of Marshalltown, Iowa. It was shown during the largest farming field days event held in Iowa up to that time.
Only 100 8010s were built, and 99 of those were rebuilt at the factory and re-released as 8020s in 1960.671960s: New Generation. John Deere 3020To introduce its New Generation tractors to all of its dealers in a single day, the company chartered planes to fly more than 5,000 people to, on August 30, 1961. Deere put their new tractors on display outside the and inside. The day would mark the release of a revolutionary line of farm tractors with sleek new styling by Henry Dreyfuss that would soon become the standard all other farm tractors would be measured. These tractors were the 1010, 2010, 3010 and.These were soon followed by the model 5010 standard introduced in 1962.
The 5010 was the first to exceed 100 hp at the PTO and drawbar. Designed for the western wheatlands, the 5010 was never available as a row crop model. In 1963 the 3010 and 4010 were replaced by the and 4020.
The 4020 is one of the most popular tractors Deere and company has ever made. The year 1965 brought the 5020 standard, which was the industry's most powerful two-wheel-drive model, along with the 1020, 2020, and 54 hp model 2510. By 1966 Sales of the 4020 accounted for 48% of all John Deere tractor sales. Also that year the row crop version of the 5020 was introduced.In the late 1960s John Deere pioneered the roll-over protection structure to protect the farmer from injury in the event of a tractor roll-over. John Deere invited the competition to view a demonstration of its new Roll-Guard. Deere recommended that all tractors include this safety feature and offered to share its design and test data with its competitors. Deere also encouraged farmers to retro-fit their tractors with this safety feature, and offered Roll Guards at cost to farmers who wished to install them on their older New Generation tractors.In 1968 seven new models appeared: the 820, 920, 1520, 2520, 4000, 4520, WA-14, and WA-17.
The WA-14 and WA-17 were articulated four-wheel-drive tractors. The 4520 was John Deere's first turbocharged tractor. The 3020 and 4020 were updated with new features, and the 5020 model had a power increase to an industry leading 141 hp. The 4000 was a high horsepower-to-weight tractor, designed to be a 'runner' rather than a 'lugger'. The 4000 used the same engine as the popular 4020, but weighed almost 1000 lbs less. According to Deere the 4000 could, in the same amount of time, pull a 4-bottom plow fast enough to cover the same acreage as a 4020 pulling a 5-bottom plow.
The John Deere 4000 was also an economy tractor, providing the same horsepower as the 4020 with fewer features and smaller rear axles.1970s Generation II During the 1970s, John Deere introduced 36 new models. In 1972 John Deere introduced the Generation II tractors. Generation II was characterized by the optional Sound Guard body which was the first truly successful integrated tractor cab.
This innovative cab was isolated from the tractor by large rubber bushings which dampened vibrations, and the interior was insulated with foam to reduce noise and protect the operator from extreme temperatures outside. A foam pad on the firewall and sheets of lead under the dash greatly reduced engine noise inside the cab. The Sound Guard body also featured a rounded front windshield with an integrated door.
The door post was in line with the exhaust and air intake pipes pipe through the hood for the best forward visibility possible. Fully integrated heating and air conditioning was standard equipment, and it also featured windshield wipers, a dome light, a red interior lamp to illuminate the gear shift levers and hydraulic controls during nighttime operation, and speakers for an optional AM/FM radio which many farmers added because they found the cab so quiet they could actually hear it. John Deere Model B tractor 70 series The spring of 1993 the four new 70 Series Power Plus 4WDs were introduced. These were the 250 hp 8570, 300 hp 8770, and a new model the 350 hp 8870. And the first 400-horsepower tractor, the 8970.
These tractor were equipped with an electronic power bulge that would kick in when tough field conditions were encountered. Later in the summer the 3055 and 3255 were replaced with the 92 hp 7200 and 100 hp 7400.8000 series 1994 was a red letter year in tractor development for John Deere because that year brought about the most revolutionary tractors the industry had seen up to then. 1994 was the last year of the Sound Guard body with the last one built being a 2WD 4760 model. It was manufactured on 1994 May 25. This ended a 22-year run for sound guard tractors that were widely regarded as the most successful tractors ever built. The new 8000 Series tractors were introduced with state-of-the-art features. The 160 hp 8100, 180 hp 8200, 200 hp 8300 and 225 hp 8400.
These four 8000 Series tractors were so far ahead of their time that it would be another four years until a competitor had tractors that were similar to them. One lone utility tractor, the 73 hp 5500 was added in the fall of 1995.TEN series upgrades 1996 saw 13 new tractors debuted at a big dealer meeting in. First all of the 7000 Series tractors were replaced the five 7000 TEN Series tractors. These were the 95 hp 7210, 105 hp 7410, 115 hp 7610, 130 hp 7710, and 150 hp 7810. But the big news came with the 8000T Series rubber belted track tractors.
There were the 8100T, 8200T, 8300T and 8400T. These built upon the 8000 Series wheeled tractors. The 70 Series tractors were replaced by the four 9000 Series tractors at 260 hp, 310 hp, 360 hp and 425 hp.
These were the 9100, 9200, 9300 and 9400. 1997 brought seven new tractors, three in the Advantage Series and four in the 5000 TEN series models. The three advantage models were the 85 hp 6405, 95 hp 6605, and 105 hp 7405. The 45 hp 5210, 55 hp 5310, 65 hp 5410, and 75 hp 5510 represent the 5000 TEN tractors. The spring of 1998 revealed the four 6000 TEN tractors.
These were the 65 hp 6110, 72 hp 6210, 80 hp 6310, and 90 hp 6410. Another new addition to the long green line in 1998 was the six 4000 Series compact diesel tractors. These were the 20 hp 4100, 21.5 hp 4200, 32 hp 4300, 36 hp 4400, 39 hp 4500, and 43 hp 4600. An Advantage Series 30 hp 790 compact diesel tractor was added to round things out.T tracked versions During the fall of 1998 John Deere had a 360 hp prototype 9300T track tractor at at least three farm shows.
During August 1999 the company had another dealer meeting in. It was here that the 360 hp 9300T and 425 hp 9400T were revealed to their dealers.
A 115 hp 7510 that came with full four-wheel drive was added. As a result, the 7610 was kicked up to the 120 hp and 7710 up to 135 hp. The 8000/8000T Series tractors were replaced with the 165 hp 8110/8110T, 185 hp 8210/8210T, 205 hp 8310/8310T, and 235 hp 8410/8410T.2000s. In the Compact utility sector the 790 at 27 hp, similar to the previous 770, and the 990 at 41 hp were introduced.
The 990 was a combination of the old 1050 and the previous 970. They would last till 2007, at which time John Deere re badged them. They exist in 2012 as the 3005 ( 790) and the 4005 ( 990). In the compact and now subcompact segment these are all that is left that is not hydrostatic. The year 2000 was not an active year for new John Deere tractor launches but did yield the 48 hp 4700. But the year 2001 produced 32 new green-and-yellow tractors. Starting with the 40 hp 990 Advantage Series compact diesel tractor this was only the beginning.
Two new 5005 Series Advantage were also added. These were the 45 hp 5105 and 53 hp 5205.
Early in 2001 the 5020 Series utility tractors was introduced. These were the 45 hp, 55 hp 5320, 65 hp 5420, and 75 hp 5520. But the big news for John Deere came in August 2001 in a dealer meeting in where 24 new tractors from 65 to 450 horsepower were introduced. Breaking things down these were the 6003, 6020, 8020/8020T, 9020 and 9020T Series tractors. These were the 85 hp 6403, 95 hp 6603, 65 hp 6120, 72 hp 6220, 80 hp 6320, 90 hp 6420 in the smaller 6000 Series tractors. In the row crop tractor the ten models were the 170 hp 8120/8120T, 190 hp 8220/8220T, 215 hp 8320/8320T, 235 hp 8420/8420T, and 256 hp 8520/8520T. As has been the case since 1996 John Deere has been the only company to offer row crop tractors in both wheel and rubber tracks.
The 9000 Series 4WD were replaced with the 280 hp 9120, 325 hp 9220, 375 hp 9320/9320T, 425 hp 9420/9420T, and the largest John Deere tractor in history up to that point the 450 hp 9520/9520T. The 8020/9020 tractors got features like Independent Link Suspension and ActiveSeat to give the farmer a more comfortable and productive day in the field.4000 TEN upgrade. 2002 - Nine new 4000 TEN Series tractors. 1st Quarter - the 20 hp 4110, 18 hp 4010, 20 hp 4115, 28 hp 4210, 32 hp 4310, 35 hp 4410, 39 hp 4510, 44 hp 4610, and 48 hp 4710. 3rd quarter the smaller 7020 Series tractors debuted.
These went from 95 to 125 horsepower and were the 95 hp 7220, 105 hp 7320, 115 hp 7420, and 125 hp 7520. Also added were the 6015 Series which were the 72 hp 6215, 85 hp 6415, 95 hp 6615, and 105 hp 6715. In early 2003 a IVT transmission was added to the options for the 7710 and 7810 tractors. A new 22 hp 2210 compact diesel tractor was also added.
2003 - (summer) three new 5003 tractors, the 44 hp 5103, 53 hp 5203, and 64 hp 5403. In August that the company had a big dealer meeting in.500 hp models arrive One thing the dealers in attendance saw that did not appear at 'Deere.com' until March 2004 was the new 500 hp 9620. The 9620 came after two of their competitors introduced 500 hp 4WDs.7×20 series In Columbus the three larger 7000 TEN tractor were replaced with the 140 hp 7720, 155 hp 7820, and the new 170 hp 7920. The 7610 was discontinued. 2004 brought the 36 hp 4120, 40 hp 4320, 47 hp 4520, and 52 hp 4720. October had the 5025 Series utility tractor introduced. These were the 45 hp 5225, 55 hp 5325, 65 hp 5425, and 75 hp 5525.
In 2005 John Deere introduced 15 new tractors. The first models were the 3020 Series tractors. The 29.5 hp 3120, 32.5 hp 3320, 37 hp 3520, and 41 hp 3720. Also added was the 18 PTO-hp 2305.
In the late summer the 9320, 9420 and 9520 were made into scraper specials to meet a niche market. In the annual dealer convention was held in in August 2005 were the company brought out the 8030/8030T Series row crop tractors. There were five wheeled models and three tracked models. The following were introduced:. The 180 hp 8130, 200 hp 8230, 225 hp 8330, 250 hp 8430, 277 hp 8530, 200 hp 8230T, 235 hp 8330T, and 255 hp 8430T.
When tested in Nebraska the 8430 was tested as the most row crop tractor ever tested. 2006 The Annual dealer meeting was held in.The Launches included:.
The 32 hp 3203, and 74 hp 5403. The Omaha get together produced the 6030 Premium and the large 7030 Series tractors. The smaller. 6030 Series of the 75 hp 6230, 85 hp 6330, and 95 hp 6430.
7030 series of the 140 hp 7630, 152 hp 7730, 165 hp 7830, and 180 hp 7930.2007 John Deere brought out a lot of new tractors in 2007 with 32 models in all. The year began with the introduction of the 5603 and 5625, both these are 82 hp and are a further extension of the 5003 and 5025 Series tractors.The big meeting was held in August 2007 in. At the Ohio meeting the dealers saw four new nursery and greenhouse tractors which would not appear at 'Deere.com' until February 5, 2008. These would be the;. 21 hp 20A, 76 hp 76F, 83 hp 85F, and 96 hp 100F.
PTO horsepower on these four tractors are 17, 66, 73, and 83 respectively. A new Series of 5003 tractors launched in the summer consisting of the;. 38 hp 5103, 47 hp 5203, 55 hp 5303, and 64 hp 5403.In the Cincinnati dealer meeting the dealers saw the regular 6030/7030 and the Premium 6030 Series tractors. The 75 hp 6230, 85 hp 6330, 95 hp 6430, 100 hp 7130, 110 hp 7230, and 125 hp 7330. New 8295 R 2017 buildThese would be the 8R/8RT Series tractors. These would be the 8235R, 8260R, 8285R, 8310R, 8335R and 8360R wheel tractors ranging from 235 to 360 engine horsepower.
The PTO is 192, 213, 234, 25, 276 and 296 hp for the six tractors. Besides the six wheel tractors, three new 8RT track tractors would be added too. There would be the 310-360 engine hp 8310RT. 8335RT and the 8360RT. Power-take off horsepower for is 247, 268 and 288 respectively. One of the major changes with these nine green-and-yellow tractors was the new PowerTech PSX 548-cubic-inch dual turbocharged diesel. This is an Interim Tier 4 (IT4) diesel engine.
On January 1, 2011 EPA Tier 4 regulations will begin thus the new PowerTech diesel in these tractors. Despite their competitors going with SCR to counter this John Deere will be using EGR-Exhaust Gas Recirculation. To tell these new 8R tractors apart from the 2010 tractors John Deere put new wrap-around lights up front. Archived from on 2008-04-03. Retrieved 2008-07-02. Cite uses deprecated parameter deadurl= ; Cite web requires website=.
Frey, Donald N. (September 1, 2009). Engineering Management Journal. Retrieved 2010-03-30. Placard at display. Placard at display.
Rukes, B. John Deere Industrials. Retrieved 2015-05-06.
Cite web requires website=. Archived from on 2008-05-26. Retrieved 2008-06-10. Cite uses deprecated parameter deadurl= ; Cite web requires website=. Rudolphi, Josie M.; Campo, Shelly; Gerr, Fred; Rohlman, Diane S. Journal of Adolescent Health. 62 (5): 605–611.
www.deere.com. Retrieved 2019-01-03.External links Wikimedia Commons has media related to. Official Website.