We're actually hoping to find photos of the storefront or even inside the store if anyone runs across one. There's also an apparent recorded interview that my grandmother gave to a radio program "World of Dance" in 1967. It includes interviews with "Merle Lister, Erick Hawkins, and Bertha Pollack, 1967" and is apparently held at the Jerome Robbins Dance Division at the Library of Performing Arts. I've been in contact with an archivist who believes it was digitalized and that I will be be able to have it. It is supposed be approximately 7 minutes in length: Alvin H. Reiss, host on the radio program World of Dance, introduces his guest Bertha Pollack, a specialist seller of dance books, at her store Ziegfield Bookshop in New York City; Pollack speaks about her business including her specialization in ballet; her customers; and books she would like to have available [concluding remarks of Reiss; announcements made by Horosko; music and closing remarks by unidentified male]. Hopefully this will add some more light, directly from the source.