Singh, Y. K. (2006). Environmental Science. New Age.
Chicago Style (17th ed.) ZitazioaSingh, Y. K. Environmental Science. New Delhi: New Age, 2006.
MLA (9th ed.) ZitazioaSingh, Y. K. Environmental Science. New Age, 2006.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.