Franklin

MLA

Helvarg, David. Blue Frontier : Dispatches From America's Ocean Wilderness. 2nd ed. San Francisco: Sierra Club Books, 2006.

APA

Helvarg, D. (2006). Blue frontier : dispatches from America's ocean wilderness. 2nd ed. San Francisco: Sierra Club Books.

Chicago

Helvarg, David, Blue Frontier: Dispatches From America's Ocean Wilderness. 2nd ed. San Francisco: Sierra Club Books, 2006.