Wolken was the married name of my grandfather's sister, Chaje (aka, Fani) Wolken. Her maiden name was Sonntag.
Her husband was Abraham Leib Wolken who was born in Tarnopol, Poland in 1876. Chaje was born in 1891 or 1893 in Jaroslau, Poland but they resided in Vienna. Abraham had an exporting / importing business of fine arts but died sometime before 1935 I believe. Chaje ran a candy shop in Vienna on Taborstrasse.
I learned through Vienna records that Chaje was murdered and died in October 1942 in Minsk - the place where she had been deported to when she was taken from Vienna - she was only age 50 or 51 at the time. I don't know if she had any children or not. Abraham Wolken had a sister, (her name appears on the Jewishgen.org website under the Poland Record Index - but other than that, I don't have any information on them. I recall seeing the Wolken surname in the Midwest, but wasn't sure if they were or weren't related to Abraham's family. Perhaps just the same last name - don't know. Good-luck in your search..