Kumra, V. K., Nag, P., & Singh, J. (1997). Geography and environment. Concept Pub.
Chicago-čujuhus (17. p.)Kumra, V. K., Prithvish Nag, juo Jagdish Singh. Geography and Environment. New Delhi: Concept Pub, 1997.
MLA-čujuhus (9. p.)Kumra, V. K., et al. Geography and Environment. Concept Pub, 1997.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.