People and Planet. IPPF.
Chicago Style (17th ed.) CitationPeople and Planet. EN: IPPF.
MLA引文People and Planet. IPPF.
警告：這些引文格式不一定是100％准確.
APA引文
People and Planet. IPPF.
Chicago Style (17th ed.) CitationPeople and Planet. EN: IPPF.
MLA引文People and Planet. IPPF.