APA aipamena

Gurcharan Singh. (2000). Pollution to purity of environment.

Chicago Style aipamena

Gurcharan Singh. Pollution to Purity of Environment. New Delh, Deep & Deep Publications, 2000.

MLA aipamena

Gurcharan Singh. Pollution to Purity of Environment. 2000.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.