National Philatelic Museum
1950 International Airpost Exhibition : September 16th-October 11th 1950 at National Philatelic Museum under the auspices of American Air Mail Society and National Philatelic Museum in conjunction with 27th annual convention American Air Mail Society, September 22 thru 24, 1950. - Philadelphia : National Philatelic Museum, [1950] - National Philatelic Museum ; v. 2, no. 7 .
Spine title: Airpost 1950 exhibition.
Air mail stamps
Postage stamps
1950 International Airpost Exhibition : September 16th-October 11th 1950 at National Philatelic Museum under the auspices of American Air Mail Society and National Philatelic Museum in conjunction with 27th annual convention American Air Mail Society, September 22 thru 24, 1950. - Philadelphia : National Philatelic Museum, [1950] - National Philatelic Museum ; v. 2, no. 7 .
Spine title: Airpost 1950 exhibition.
Air mail stamps
Postage stamps