Tiwari, V.M.; Wahr, J.; Swenson, S. (2009). "Dwindling groundwater resources in northern India, from satellite gravity observations". Geophysical Research Letters. 36 (18). L18401. Bibcode:2009GeoRL..3618401T. doi:10.1029/2009GL039401.
Tiwari, V.M.; Wahr, J.; Swenson, S. (2009). "Dwindling groundwater resources in northern India, from satellite gravity observations". Geophysical Research Letters. 36 (18). L18401. Bibcode:2009GeoRL..3618401T. doi:10.1029/2009GL039401.