Singh, S. (1974). Co-operatives in Papua New Guinea. New Guinea Research Unit, Australian National University.
Lua i Stíl Chicago (17ú heag.)Singh, Sumer. Co-operatives in Papua New Guinea. Port Moresby: New Guinea Research Unit, Australian National University, 1974.
Lua MLA (8ú heag.)Singh, Sumer. Co-operatives in Papua New Guinea. New Guinea Research Unit, Australian National University, 1974.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.