Sherma, Y. P., A. K. Singhvi, D. P. Agrawal, B. Gaulin, and F. T. Hedgcock. “Physical Research Laboratory TL Dates - 1981 (II)”. Ancient TL 5, no. 2 (March 21, 1981): 6–8. Accessed May 1, 2025. https://www.ancienttl.org/article/view/6309.