Cita APA (7a ed.)
Stanley Gibbons Publications Ltd & Allen, E. Collect British Stamps: A Stanley Gibbons Checklist of the Stamps of Great Britain (Vigésima edición.).
Cita Chicago Style (17a ed.)
Stanley Gibbons Publications Ltd y Eric Allen. Collect British Stamps: A Stanley Gibbons Checklist of the Stamps of Great Britain. Vigésima edición.
Cita MLA (9a ed.)
Stanley Gibbons Publications Ltd y Eric Allen. Collect British Stamps: A Stanley Gibbons Checklist of the Stamps of Great Britain. Vigésima edición.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.