APA (7th ed.) Citation

Rosenthal, J. (2008). Big Brother: Getting Bigger? National Geographic Traveler, 25(5), 18.

Chicago Style (17th ed.) Citation

Rosenthal, John. "Big Brother: Getting Bigger?" National Geographic Traveler 25, no. 5 (2008): 18.

MLA (9th ed.) Citation

Rosenthal, John. "Big Brother: Getting Bigger?" National Geographic Traveler, vol. 25, no. 5, 2008, p. 18.