Rajkhowa, S. and Seth, S.K. 1961. The Effect of Periodicity, and Length and Depth of Freshening on the Yield of Resin from <I>Pinus roxburghii</I>. Indian Forester. 87, 12 (Dec. 1961), 724–730. DOI:https://doi.org/10.36808/if/1961/v87i12/24605.