You can find more information on the info page
supplement to the Mitteldeutsche Philatelisten-Zeitung
Russian Postage Stamps 1917-1923 Forgery Guide 9R
half-linen
650 perforations are illustrated
Crüsemann, Fr., Deutsche Marineschiffspost - Handbuch und Stempelk ... AUT-Raupp You can find more informationCrsemann, Fr., German naval ship post handbook and stamp catalogue, part 1, the period up to the outbreak of World War 1914, 12 booklets complete (+ the first of 2 supplementary deliveries bound, the other only appeared in 1999 and is enclosed loose)) and Crsemann Schlimgen, German naval ship post handbook and stamp catalogue, part 2: 1914 19, 1978, 7 booklets complete, together in 3 full linen volumes, identically bound, the paper slightly browned