Bibiliography

"HISTORY OF Ultimate Disc- Page 1 of 2" HISTORY OF Ultimate Disc- Page 1 of 2 | Court & Field Dimension Diagrams in 3D, History, Rules – SportsKnowHow.com. Internet Marketing Unlimited, Corp, n.d.24 Jan, 2019
http://www.sportsknowhow.com/ultimate-disc/history/ultimate-disc-history.shtml