S.L. & Co. – early 20th century postcard publisher (1906-1918), Langdorf printed his postcards in Germany. His logo was an emblem of a winged circle enclosing the letters "SL & Co."
“Samuel Langdorf & Co., New York, New York,” Southwest Harbor Public Library, accessed October 8, 2024, https://swhpl.digitalarchive.us/items/show/10455.Item 14412