APA Style
Billings, John J.. (1987).
The Ovulation Method: Natural Family Planning (Edisi 4 (Cetakan 2)).
Collegeville, Minnesota:
The Liturgical Press.
Chicago Style
Billings, John J..
The Ovulation Method: Natural Family Planning.
Edisi 4 (Cetakan 2)
Collegeville, Minnesota:
The Liturgical Press,
1987.
Text.
MLA Style
Billings, John J..
The Ovulation Method: Natural Family Planning.
Edisi 4 (Cetakan 2)
Collegeville, Minnesota:
The Liturgical Press,
1987.
Text.
Turabian Style
Billings, John J..
The Ovulation Method: Natural Family Planning.
Edisi 4 (Cetakan 2)
Collegeville, Minnesota:
The Liturgical Press,
1987.
Print.