- Author: Fritz Klein, Karen Yescavage, Jonathan Alexander
- Language: English
- Year: 2004
- Author: Fritz Klein (editor), Karl Drechsler (editor), Wolfgang Ruge (editor), Joachim Streisand (editor)
- Language: German
- Year: 1976
- Author: Fritz Klein (editor)
- Language: German
- Year: 1977
- Author: Serena Anderlini-D'Onofrio Fritz Klein (editor)
- Language: English
- Year: 2005
The Bisexual Option
mobi
- Author: Fritz Klein MD
- Language: English
- Year: 1993
- Author: Dr. Fritz Klein-Blenkers (auth.)
- Language: German
- Year: 1964