Llinynnau.
Foster, John,1941 October 12-
Parry, Rhiannon.
Jones, Glenda.
Parry, Palmer.
University College of Wales (Aberystwyth, Wales).Centre for Educational Studies.
Aberystwyth : Canolfan Astudiaethau Addysg,
1994.
Arg. Saesneg gwreiddiol = Original English ed: Collins Educational, 1986
Interpersonal relations