He was ''J.Dr.'' per ''High-Life-Almanach: Adressbuch der Gesellschaft Wiens und der österreichischen Kronländer, 1913'', at ancestry.com. Resided Wien III, Rennweg 5. His signature on the back of niece's 1905 birth record is [https://familysearch.org/pal:/MM9.3.1/TH-1951-2580...MMGD-2ZK:n2136869105 here].