Development of international air post
Collection of stamps cards and covers illustrating the development of international air post 1870-1950 / amassed by Miss Winifred Penn-Gaskell. 67: Folder of twelve album sheets mounted by Frank Godden Ltd with vignettes, cards, original watercolours and designs, some Swiss, 1912-1914. 67/10: One sheet with 3 essay proofs of Mons. Vibert's design for proposed official Swiss Air stamps. .