Mystery Cards -Female Fashion Illustrators

I have seven on these mysterious cards. Each one has a female Fashion Illustrator featured with a New York address and a phone number. They are large 6" x 9", and printed on cardstock. Some are printed on the back "Please file this card under Fashion". The artists are Gladys Rockmore Davis, Helen Ketchum, Helen A. Johnson, E. Ann Quackenbush, Elisabeth Hughes, Inga Stevens Pratt, and Anna Nasvik. I am wondering if they were designed for a ad agency or magazine art directors or even sewing pattern companies? Each on seems to show a few different styles, like a mini portfolio. There are no dates, but the fashions look mostly forties. What do you know about these?

I just heard from Bill Higgins, who knows a lot about Inga Stevens Pratt. She lead a fascinating life and you can learn more at http://en.wikipedia.org/wiki/Inga_Stephens_Pratt_Clark.
Thanks Mr. Higgins!