The complete set in detail

R435
Sc.No. B38
1931 - The Zwinger at Dresden, welfare fund : Watermark 'network' - green ; 8 Pfg. + 4 Pfg.

R436
Sc.No. B39
1931 - Town Hall at Breslau, welfare fund : Watermark 'network' - carmine ; 15 Pfg. + 5 Pfg.

R437
Sc.No. B40
1931 - Heidelberg castle, welfare fund : Watermark 'network' - blue ; 25 Pfg. + 10 Pfg.

R438
Sc.No. B41
1931 - The Holstentor at Lübeck, welfare fund : Watermark 'network' - brown ; 50 Pfg. + 40 Pfg.