Gaya APA

Associates, P., Massachusetts, S. (1977). Study Guide for LIFE : Cells, Organism, Population (Ed. 1). Massachusetts: Sinauer Assocites, Inc..

Gaya MLA

Associates, P.S.., Massachusetts, Sterling. "Study Guide for LIFE : Cells, Organism, Population". Ed. 1 Massachusetts: Sinauer Assocites, Inc., 1977. Text.