Shapiro, G. L. (1985). Factors influencing the variance in sign learning performance by four juvenile Orangutans (Pongo pygmaeus).
Chicago Style (17th ed.) CitationShapiro, Gary Louis. Factors Influencing the Variance in Sign Learning Performance by Four Juvenile Orangutans (Pongo Pygmaeus). 1985.
MLA (8th ed.) CitationShapiro, Gary Louis. Factors Influencing the Variance in Sign Learning Performance by Four Juvenile Orangutans (Pongo Pygmaeus). 1985.
Warning: These citations may not always be 100% accurate.