Welburn, T. (1983). Advanced structured COBOL: Batch, on-line, and data-base concepts.
Chicago-referens (17:e uppl.)Welburn, Tyler. Advanced Structured COBOL: Batch, On-line, and Data-base Concepts. 1983.
MLA-referens (9:e uppl.)Welburn, Tyler. Advanced Structured COBOL: Batch, On-line, and Data-base Concepts. 1983.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.