Gaya APA

Davis, G, B. et al (1971). ELEMENTARY STRUCTURED COBOL A STEP BY STEP APPROACH . NEW YORK: Mc Graw-Hil Book Company.

Gaya MLA

Davis, Gordon, B.. et al. "ELEMENTARY STRUCTURED COBOL A STEP BY STEP APPROACH". NEW YORK: Mc Graw-Hil Book Company, 1971. Text.