30 Pfg Konstanzer engineer congress, 2 edition, correctly franked mixed franking with 10 Pfg and 20 Pfg Gustav Werner on registered letter from "Cologne 5 4.11.49" to Alfeld and the cord, photo expertize Schlegel BPP: "defects to the stamps are indistinguishable. The letter is correctly franked franked. ", Michel 3.000.-