Thakur, P. (2007). Environmental studies. ABD Publ.
Lua i Stíl Chicago (17ú heag.)Thakur, P. Environmental Studies. Jaipur: ABD Publ, 2007.
Lua MLA (9ú heag.)Thakur, P. Environmental Studies. ABD Publ, 2007.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.