Gaya APA

GEOGRAPHIC, N. (2010). NATIONAL GEOGRAPHIC : Mount St. Helens. VOL. 217. NO. 8. MAY 2010 (VOL. 217. NO. 8. MAY 2010). WASHINGTON. D.C.: NATIONAL GEOGRAPHIC.

Gaya MLA

GEOGRAPHIC, NATIONAL. "NATIONAL GEOGRAPHIC : Mount St. Helens. VOL. 217. NO. 8. MAY 2010". VOL. 217. NO. 8. MAY 2010 WASHINGTON. D.C.: NATIONAL GEOGRAPHIC, 2010. Koleksi Khusus.