Anthony Dickins, A Guide to Fairy Chess Contains many chess variants. This book has an emphasis on fairy chess problems, i.e., problems in chess variants. Published by Dover in 1971. The book may be hard to find, but a more recent German translation may be easier to obtain. 1 A 136 page book on Chinese Chess.
Personal cheque is okay.
Information about this book . Sam Sloan, Chinese Chess for Beginners Published by Ishi Press. Review of this book by Michael Keller . Material needed to win or draw various endings. Descriptions of popular opening variations.