Cita APA (7a ed.)
National Postal Museum & Gammons, T. The Early Days of the Postal Service.
Cita Chicago Style (17a ed.)
National Postal Museum y Tony Gammons. The Early Days of the Postal Service.
Cita MLA (9a ed.)
National Postal Museum y Tony Gammons. The Early Days of the Postal Service.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.