Gaya APA
Powell, J, S. (1992).
10 (Sepuluh) laku hidup bahagia. : Happiness is an inside job. 1989 .
Yogyakarta:
Kanisius.
Gaya MLA
Powell, John,, SJ.
"10 (Sepuluh) laku hidup bahagia. : Happiness is an inside job. 1989 ".
Yogyakarta:
Kanisius,
1992.
Buku.