1926, International Esperanto Congress, 7k blue green and red, 14k blue green and violet, complete set of two with perforation 11½, each one with side margin, excellent quality, full OG, NH, VF and rare, Z. Mikulski certificate, C.v. $8,500 as hinged, Est. $6,000-$7,500

1926, International Esperanto Congress, 7k and 14k , complete set of two and a single of 7k, used on front and reverse respectively of registered cover sent from the Congress to Germany, tied by green "10.8.26" special date stamp, Leipzig "15.8.26" arrival marking on the back, mostly VF, Est. $150-$200

100.00