Prague Town Hall mathematical clock, Theory of Functions dia (Czechoslovakia 1987)

06 July (Czechoslovakia ) within release Anniversary goes into circulation Stamp Prague Town Hall mathematical clock, Theory of Functions dia face value 50 Czechoslovak haléř

Stamp Prague Town Hall mathematical clock, Theory of Functions dia in catalogues
Michel:	Mi:CS 2918
Yvert et Tellier:	Yt:CS 2729
POFIS:	POF:CS 2801

Stamp is square format.

Also in the issue Anniversary:

• Stamp - Prague Town Hall mathematical clock, Theory of Functions dia face value 50;
• Stamp - Geographical measurement (1672), Earth fold and Brownian mot face value 50;
• Stamp - J. M. Petzval (1807-1891), J. Strouhal (1850-1922) and V. Ja face value 50;