Singh, Y. K. (2006). Environmental Science. New Age.
Chicago-čujuhus (17. p.)Singh, Y. K. Environmental Science. New Delhi: New Age, 2006.
MLA-čujuhus (9. p.)Singh, Y. K. Environmental Science. New Age, 2006.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.