1966 PLATE PROOF COB19, Exhibition specializovaných branches 60h, proof print unfinished gravure (neprorytý wedge [ ˇ ] above Č) stamp. for envelope in black color on/for smooth carton without gum, with signature J. Herčík; very fine
1968 PLATE PROOF COB23, PRAGA 1968 60h, proof print unfinished gravure (neprorytý wedge [ ˇ ] above Č) stamp. for envelope in/at grey-green color on/for smooth carton without gum, with signature J. Herčík; very fine
1982 PLATE PROOF COB75, Conference ITU Nairobi 6Kčs, proof print unfinished gravure (neprorytý wedge [ ˇ ] above Č) stamp. for envelope in/at definitive colour joined printing on/for smooth paper without gum, wide margins, with signature J. Herčík; very fine
1975 PLATE PROOF Husák 1Kčs, print definitive gravure with 1Kčs in red color for postal stationery cover, on/for strong white carton in/at miniature sheet arrangement; very fine, expert Benes