Limited, Oil and Natural Gas. "Shareholding pattern"(PDF). Archived(PDF) from the original on 21 September 2021. Retrieved 29 July 2020. {{cite web}}: |last= has generic name (help)
"Annual Report 2012-13"(PDF). ONGC. 29 May 2013. Archived(PDF) from the original on 9 November 2013. Retrieved 9 November 2013.
"History". ONGC. Archived from the original on 9 November 2013. Retrieved 10 November 2013.
Limited, Oil and Natural Gas. "Shareholding pattern"(PDF). Archived(PDF) from the original on 21 September 2021. Retrieved 29 July 2020. {{cite web}}: |last= has generic name (help)
"Annual Report 2012-13"(PDF). ONGC. 29 May 2013. Archived(PDF) from the original on 9 November 2013. Retrieved 9 November 2013.