These charming coloured etchings are by the Austrian printmaker Ludwig Burgel (1901-1980), an artist who had studied at the Vienna Art School and went to create these prints of the Austrian landscape.
Gerrie the Linosaurus has already written a posting about this artist, which should be viewed for the full story and with more pictures. CLICK HERE to view.
The original labelling below helps clarify that the note "Og Rad" isn't the titled but an abbreviation of "Original Radierung" or Original Etching.
If the number 166 refers to his own catalogue, then he was prolific.