APA (7th ed.) Zitazioa

Heap, G. (1992). Structures approach to systems development. McGraw-Hill.

Chicago Style (17th ed.) Zitazioa

Heap, Gary. Structures Approach to Systems Development. London: McGraw-Hill, 1992.

MLA (9th ed.) Zitazioa

Heap, Gary. Structures Approach to Systems Development. McGraw-Hill, 1992.