1.1 Aviso, Relation oder Zeitung 16
1.2 Georg Keller added this piece of paper to a letter by Heinrich Schute to Bartholomäus Wolfsberg, Hamburg, 18 March 1649, Wolfsbergs samling, E 6099, RA 29
1.3 Letter by Martin Schumacher to Georg Keller, secretary of Johan Adler Salvius, Hamburg 6 September 1644, Salvius samling E 5273, RA 46
2.1 With permission of Åland post Ab,
2.2 Undated project by a citizen of Reval, Heinrich Diener, about a postal system in the Swedish Baltic provinces, Kanslikollegium, G V, vol. 1, RA 80
2.3 Kanslikollegium, G V, vol. 1, RA 94
2.4 Kanslikollegium, G II f, vol. 1, RA 106
2.5 Kanslikollegium, G II f, vol. 1, RA 110
3.1 Title page of tract by Weise Christian, Schediasma curiosum de lectione novellarum […] (Weissenfels: Brühl, 1676),
3.2 Gregor Wintermonat, Continuatio XIII. Der Zehenjährigen Historischen Relation (Leipzig: Lamberg, 1613), title page
3.3 Christian Weise, Curiöse Gedancken von Deutschen Brieffen […] (Dresden: Mieth, 1691).
3.4 August Bohse, Der allzeitfertige Brieffsteller […] (Frankfurt am Main and Leipzig: Boetius, 1692) Title page:
4.1 Picture taken by Heiko Droste 173
4.2
User: Gyddanyzc 214
5.1 Kanslikollegium, G V, vol. 1, RA 239
5.2 Polonica, vol. 70, RA 249
5.3 Fond 230, nimistu 1, 1384-BL 5 II, Archiv der Hansestadt Reval (Tallinna Linnaarhiiv) 257