Gopalakrishnana, P. (1990). Purchasing and materials management.
Lua i Stíl Chicago (17ú heag.)Gopalakrishnana, P. Purchasing and Materials Management. New Delhi, 1990.
Lua MLA (9ú heag.)Gopalakrishnana, P. Purchasing and Materials Management. 1990.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.