Gaya APA
D., J, K, B, P.
(1973).
Ways to Develop Will-Power
(
Cetakan 2)
.
Wellingborough:
Weatherby Woolnough.
Gaya MLA
D., John, Kennedy,M.A.,, B.D.,, Ph..
"Ways to Develop Will-Power".
Cetakan 2
Wellingborough:
Weatherby Woolnough,
1973.
Text.