平原印第安人手语(英語:Plains Indian Sign Language,PISL;法語:Langue des Signes Indienne des Plaines;西班牙語:Lenguaje de Signos Indio de las Llanuras),又称平原手语、平原手势谈话(Plains Sign
213–29. in JSTOR (页面存档备份,存于互联网档案馆) Gates, Paul W. "Homesteading in the HighPlains". Agricultural History (1977): 109–33. in JSTOR (页面存档备份,存于互联网档案馆) Otto
Steffy, Loren. Bonderman rides to rescue of corporate wrecks. The Journal News (White Plains, New York). Bloomberg News. March 1, 1988 [June 14, 2017]. (原始内容存档于2018-06-22)