Losoncy, L. E. (1980). You can do It¡ how to encourage yourself. Prentice Hall.
Dyfyniad Arddull ChicagoLosoncy, Lewis E. You Can Do It¡ How to Encourage Yourself. Prentice Hall, 1980.
Dyfyniad MLALosoncy, Lewis E. You Can Do It¡ How to Encourage Yourself. Prentice Hall, 1980.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.