26 Jun 1873 to 30 Jun 1875, US-Swedish Bilateral Convention
Amount due for unpaid letters: 56 öre
Part payment credited at 4 öre per cent.
Postage due paid in cash before 1 Jan 1874, then by postage due stamps.
Letter with 7 cent. Postage due 56 öre less
4 öre per cent paid; 56-7x4=28 öre.
-o-o-o-
Litterature: Bertil I. Larsson, Vår postala
konvention med USA, Postryttaren 1999, p.103-128