1. Agrawal, O. P., Narain, H., & Prakash, J. (1990). Technical studies of silver punch mark coins from Narhan (Gorakhpur U.P.), India—600 BCE–200 BCE. Journal of the Historical Metallurgy Society, 24(2), 81–88.
2. Divija, M., Singh, M., & Lal, U. S. (2018). Examination and analysis of Indian silver punchmarked coins employing WD-XRF and other noninvasive techniques. Surface and Interface Analysis, 69(10), 947–953.
3. Mookerji, R. (1960). Chandragupta Maurya and his times, Madras University, Sir William Meyer Lectures, 1940–1941 (pp. 212–218). New Delhi: Motilal Banarsidass.
4. Rao, B. S., & Nair, M. V. (1991). A study of ancient punch marked silver coins, The Indian Journal of Numismatic Society of India, Vol. LIII, Parts I & II, 195–202.
5. Rautray, T. R., Suman, A. B. N., Nayak, S., Bipin, C., Tripathy, B., Saubhagyalaxmi, D., Das, B., Manas, R., Das, E., Satya, R., Das, F., & Chattopadhyay, P. K. (2011). Analysis of ancient Indian silver punch-marked coins by external PIXE. Applied Radiation and Isotopes, 69, 1385–1389.