Singh, A. K. (2013). Science & Technology for civil services examinations. Tata Mc Graw Hill.
Dyfyniad Arddull ChicagoSingh, Ashok Kumar. Science & Technology for Civil Services Examinations. New Delhi: Tata Mc Graw Hill, 2013.
Dyfyniad MLASingh, Ashok Kumar. Science & Technology for Civil Services Examinations. Tata Mc Graw Hill, 2013.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.