Helder, C. (2014). The Ultimate book of Influence. Wiley India.
Dyfyniad Arddull ChicagoHelder, Chris. The Ultimate Book of Influence. New Delhi: Wiley India, 2014.
Dyfyniad MLAHelder, Chris. The Ultimate Book of Influence. Wiley India, 2014.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.