O'Brien Derek & Padmanabhan,Gautam Jayakumar,Navin. (2006). Penguin Landmark Quiz Book (NA.). Penguin Books.
Dyfyniad Arddull ChicagoO'Brien Derek and Padmanabhan,Gautam Jayakumar,Navin. Penguin Landmark Quiz Book. NA. New Delhi: Penguin Books, 2006.
Dyfyniad MLAO'Brien Derek and Padmanabhan,Gautam Jayakumar,Navin. Penguin Landmark Quiz Book. NA. Penguin Books, 2006.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.