MLA

Hefley, William E, and Yongsheng Wang. Economics of Unconventional Shale Gas Development. Springer International Publishing, 2015.

APA

Hefley, W. E, & Wang, Y. (2015). Economics of Unconventional Shale Gas Development. Springer International Publishing.

Chicago

Hefley, William E., and Yongsheng Wang. Economics of Unconventional Shale Gas Development. : Springer International Publishing, 2015.