Gêmau pêl /
Glover, David,1953 September 4-
Williams, Mel.
Canolfan Astudiaethau Addysg.
Aberystwyth : Canolfan Astudiaethau Addysg,
1992.
Arg Saesneg gwreiddiol = Original English ed: London: Ginn, 1992
Balls (Sporting goods)
Science