WAINWRIGHT GORDON R. (1992). S.T.E.P.S. FOR SUCCESS: SELF TRAINING IN ESSENTIAL PERSONAL SKILLS. MERCURY BOOKS.
Dyfyniad Arddull ChicagoWAINWRIGHT GORDON R. S.T.E.P.S. FOR SUCCESS: SELF TRAINING IN ESSENTIAL PERSONAL SKILLS. LONDON: MERCURY BOOKS, 1992.
Dyfyniad MLAWAINWRIGHT GORDON R. S.T.E.P.S. FOR SUCCESS: SELF TRAINING IN ESSENTIAL PERSONAL SKILLS. MERCURY BOOKS, 1992.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.