Shapiro, Gary Louis <br/><br/>
Factors influencing the variance in sign learning performance by four juvenile Orangutans (Pongo pygmaeus) / 
by Gary Louis Shapiro 
 -  1985 
 - 63 p. :  ill. ;  22 cm. 
<br/><br/>Thesis (Ph.D.) - University of Oklahama, 1985 
<br/><br/><label>Subjects--Corporate Names: </label><br/>University of Oklahama--Dissertations
<br/><br/><label>Subjects--Topical Terms: </label><br/>Orangutan<br/>Sign language<br/>Dissertations, Academic--Oklahoma