National Geographic
National Geographic Society,
 Majalah, Jurnal, Buletin
National Geographic
National Geographic Partners, {s.a.}
 Majalah, Jurnal, Buletin
Macdonald, Phil
National Geographic Traveler Thailand
National Geographic, 2009
 Buku Teks
National Geographic 100 Big Ideas
Nasional Geographic, 2009
 Buku Teks
Duty Andhika Nurkalam
Makna pemanasan global di pembaca majalah National Geographic Indonesia (NGI) = The meaning of global warming on audiences of National Geographic magazine (NGI) / Duty Andhika Nurkalam
2014
 UI - Skripsi Membership