Deutsche Katamaran-Bücher

There seem to be a lot of books on Catamaran sailing in German, and I have seen some with lots of helpful pictures. Since German is the only modern language I read without difficulty, I am wondering which of these are particularly good. Is there anybody who knows these books and can make recommendations?

Katamarane, Das Buch. von Helge Sach, Andreas Kling. Dsv-Verlag (2002)
http://www.amazon.de/exec/obidos/AS... /sr=1-1/ref=sr_1_0_1/302-5694732-2727224

Katamarane, Der Einstieg. von Helge Sach, Andreas Kling. Dsv-Verlag (1997).
http://www.amazon.de/exec/obidos/AS... /sr=1-2/ref=sr_1_0_2/302-5694732-2727224

Cat- Fun pur. Segelspaß auf zwei Rümpfen.
von Kirsten Gunkel, Helmut Hinnemann
http://www.amazon.de/exec/obidos/AS... /sr=1-9/ref=sr_1_2_9/302-5694732-2727224

Cat - Segeln. Für Einsteiger.
von Helmut Hinnemann
http://www.amazon.de/exec/obidos/ASIN/3768807436/ref=pd_bxgy_text_2/302-5694732-2727224

Das ist Cat- Segeln.
von Claus Baalmann, Volker Möhle, Thomas Weinhardt
http://www.amazon.de/exec/obidos/ASIN/3768809838/ref=pd_sim_dp_3/302-5694732-2727224

Thanks,

Jonathan