Gopal, M. (1970). An Int to Research Procedure in Social sciences (2nd.). Asia Pub House.
Lua i Stíl Chicago (17ú heag.)Gopal, M. An Int to Research Procedure in Social Sciences. 2nd. NULL: Asia Pub House, 1970.
Lua MLA (9ú heag.)Gopal, M. An Int to Research Procedure in Social Sciences. 2nd. Asia Pub House, 1970.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.