This marking belongs to well-known in Poland company of Adam Shrayer.

Toy and doll fabric of Adam Shrayer (Adam Szrajer - in Polish) was founded in 1884 in Polish town Kalish (Kalisz). But from the beginning it was a partnership - its owners are Adam Shraer and Jakub Fingerhut, Adam's father-in-law and also doll manufacturer. And only from 1910 the fabric passed to Shrayer family entirely. Since then all production begun to be marked "A.S.K", i.e. "Adam Szrajer Kalisz".
 - here's marking found on celluloid dolls.

Then celluloid era started. In early 1930's fabric produced popular Shirley Temple dolls as well and sold them in Europe and N. & S. America, including USA. All their dolls, both bisque heads and celluloid, usually have one row of six upper teeth.

On April 1939 the youngest Adam and Bertha Shrayer's son, Mechislav represented A.S.K. Company at the World exhibition in New York, where their production got a prize. But WWII begun, and Mechislav used all his money and contacts to bring to USA the most part of his family.

Mechislav Shrayer worked in administration of Ideal Toy Company, his brother Henrick founded a toy factory (its name is unknown). Mechislav passed away in 1954, Henrick - in 1981. What about Adam Shrayer - there are no any info at all.

Guide based on Doctoral Thesis of Yaroslav Dolat, Curator of Opatuvka's Museum of Industry's History in Vongrovets.
Translation from Polish/Russian into English and Guide text- by me.