Karl Koppel Weisz Bakery, Vienna Phone Book Listing (A 32, 210). See notes 3.

http://www.digital.wienbibliothek.at/wbrobv/periodical/zoom/269523

The translation of this listing is:
Bäckergewerbe (Bakery firm)
Off Ges. Offizieller Geschäftsinhaber (official manager)
Karl Kopel Weisz and Viktor Weisz
Zeich (they are entitled to sign on behalf of the company)

The address of the bakery was:
Franz Hochedlinger-Gasse 24.
Leopldstadt, Vienna, Austria
(Leopldstadt is a district of Vienna that had a high percentage of Jewish people.)
Their home was just around the corner at Floßgasse.

German: Adolph Lehmann's Allgemeiner Wohnungs-Anzeiger
English: Adolph Lehmann's General Housing Indicators

German: [Firmenverzeichnis] 2. Protokollierte Firmen.
English: [Business Directory] 2. Documented Company.

German: Nach den Veröffentlichungen des Ha Wien
English: According to the publications of Vienna