MLA

Delfs, and Helmut Knebl. Introduction to Cryptography. Springer Berlin Heidelberg, 2015.

APA

Delfs, D., & Knebl, H. (2015). Introduction to Cryptography. Springer Berlin Heidelberg.

Chicago

Delfs, and Helmut Knebl. Introduction to Cryptography. : Springer Berlin Heidelberg, 2015.