With regard to discussions on DDSG postal's activity from this thread : http://www.philaseiten.de/cgi-bin/index.pl?ST=853&CP=0&F=1 To all interested on this subject I would suggest this comprehensive book : The private ship letter stamps of the world, Part 2, Australia-Europe-South America: by S.Ringstrom and H.E.Tester, 1976 ,Skogs Trelleborg, The bibliography used by the authors to write their work is shown below :

In the above-mentioned book, the only ORSOVA Agency oval type marking is shown attached

@ March [#1]

Dear March

thank you for your advice of literature about this topic. Also the bibliography used by the authors Ringstrom Tester (1-12) is usefull. The list in the work of Hurt/Kelly 1950 mentions a few more (early references, only, of course).

Greeting
Heinz

Thanks Heinz 7 :)

The history of DDSG company and its postal activity is fascinating to me !