Bowler, B., & Bill Bowler; Sue Parminter. (2003). Happy Earth: Class book. Oxford,New York: Oxford University Press.
Dyfyniad Arddull ChicagoBowler, Bill, và Bill Bowler; Sue Parminter. Happy Earth: Class Book. Oxford,New York: Oxford University Press, 2003.
Dyfyniad MLABowler, Bill, và Bill Bowler; Sue Parminter. Happy Earth: Class Book. Oxford,New York: Oxford University Press, 2003.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.