APA Style

Obert, L., Duvall, W, I. (1967). Rock Mechanics and the Design of Structures in Rock (Cet.4). New York: John Wiley & Sons, Inc.

MLA Style

Obert, Leonard., Duvall, Wilbur, I.. "Rock Mechanics and the Design of Structures in Rock". Cet.4 New York: John Wiley & Sons, Inc, 1967. Text.