Cita APA (7a ed.)
Stanley Gibbons Publications Ltd & Mackay, J. A. Philatelic Terms Illustrated.
Cita Chicago Style (17a ed.)
Stanley Gibbons Publications Ltd y James A. Mackay. Philatelic Terms Illustrated.
Cita MLA (9a ed.)
Stanley Gibbons Publications Ltd y James A. Mackay. Philatelic Terms Illustrated.
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