Gaya APA

Litecky, C, R., Davis, G, B. (1987). Structured Cobol A Step By Step Approach . United States of America: Mc Graw Hill.

Gaya MLA

Litecky, Charles, R.., Davis, Gordon, B.. "Structured Cobol A Step By Step Approach". United States of America: Mc Graw Hill, 1987. Text.