Collection of stamps cards and covers illustrating the development of international air post 1870-1950

Collection of stamps cards and covers illustrating the development of international air post 1870-1950 / amassed by Miss Winifred Penn-Gaskell. 87: Exhibition catalogues 1925-1930. Comprising: L'Exposition Internationale des Timbres-Poste, Paris, 2-12 May 1925. 224pp; British Polar Exhibition, London, 2-15 July 1930. 18pp, relating to Franklin's balloon search message; Catalogue of a Loan Exhibition of rare and historic air mail stamps and covers, Old Bond Street Galleries London, 10-12 June 1930. 12pp; page 9 exhibits from Miss Penn-Gaskell