R. Balasubramaniam 2005, pp. 13-15, "There is strong archaeological evidence in favour of Mathura being a centre of Buddhist religious activities (and not Vaishnava worship) during the Gupta period. (...) In fact the Hindu images which appear at Mathura in the pre-Gupta days are very few in number...". R. Balasubramaniam (2005). Story of the Delhi Iron Pillar. Foundation Books. ISBN978-81-7596-278-1.
Kamachi Mudali, U.; Baldev Raj (February 2009). "Insitu corrosion investigations on Delhi iron pillar". Transactions of the Indian Institute of Metals. 62 (1): 25–33. doi:10.1007/s12666-009-0004-2. S2CID137223437.
On the Astronomical Significance of the Delhi Iron Pillar, R Balasubramaniam and Meera I Dass, Current Science, volume 86 (2004) pp. 1134–1142.[3]Archived 24 September 2015 at the Wayback Machine
On the Corrosion Resistance of the Delhi Iron Pillar, R. Balasubramaniam, Corrosion Science, Volume 42 (2000) pp. 2103 to 2129. Corrosion Science is a publication specialized in corrosion science and engineering.
Kamachi Mudali, U.; Baldev Raj (February 2009). "Insitu corrosion investigations on Delhi iron pillar". Transactions of the Indian Institute of Metals. 62 (1): 25–33. doi:10.1007/s12666-009-0004-2. S2CID137223437.
On the Astronomical Significance of the Delhi Iron Pillar, R Balasubramaniam and Meera I Dass, Current Science, volume 86 (2004) pp. 1134–1142.[3]Archived 24 September 2015 at the Wayback Machine