Singhal, R. M. and Sharma, S. D. (1979) “Infra-red Spectroscopy of the Soil Humic Acids of the Sal (<I>Shorea robusta</I>) Forests of Doon Valley”, Indian Forester, 105(9), pp. 658–663. doi: 10.36808/if/1979/v105i9/11359.