Zeppelin Post, Official Mail, Machine Cancels
Axel Frauenrath
Kaldenkirchener Str. 42, D-41063 Mönchengladbach
Tel. +49 175 228 0465, E-Mail: axel.frauenrath@t-online.de

Post Offices, Postmarks, Overprints
Hans-Jürgen Goebelbecker
Wiesenstr. 9a, D-76706 Dettenheim
Tel. +49 170 387 1200, E-Mail: haju.goe@gmx.de

Revenues
Jörg Hofmann
Lilienthalstr. 30, 42719 Solingen
Tel. +49 212 314 525, E-Mail: australien81@yahoo.de

Military and Censor Mail, Irish Movement for Independence appr. 1910 to 1923: Political and Propaganda Labels Related to Ireland
Heinz-Jürgen Kumpf
Schützengasse 6/3, A-1060 Wien
Tel. +49 170 494 1088, E-Mail: hjkumpf-fai@gmx.at

Postmarks from 1922
Harald Lützenkirchen
Glehner Weg 35, D-41464 Neuss
Tel. +49 2131 81518, E-Mail: logokrat@t-online.de

Postal Rates until 1922 (in particular rates for foreign countries)
Dr. Joachim Schaaf
E-Mail: joachim.schaaf@web.de