Crebbin, J., & Hellard, S. (2004). Please sit still. Cambridge University Press.
Dyfyniad Arddull ChicagoCrebbin, June, and Susan Hellard. Please Sit Still. Cambridge: Cambridge University Press, 2004.
Dyfyniad MLACrebbin, June, and Susan Hellard. Please Sit Still. Cambridge University Press, 2004.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.