Friedrich F Steuer, handbook and catalogue of the German colonial-forerunner - with valuation of all on Before and follower possible cancellations considering the by the German post offices abroad and colonies verifiably, different issues the used stamps of the German Reich" 4. Edition Schwaneberger publishing house, Munich, 2006.480 sides, about 900 illustrations and over 2600 valuations. (NP 128 EUR)