Next time you’re at the New York Public Library, take a look at this book:
United States. Immigration and Naturalization Service. Uniform title: Foreign versions, variations, and diminutives of English names. Title: Foreign versions of English names and foreign equivalents of United States military and civilian titles. Detroit, Mich.: Grand River Books, [197-?] Call number: APD 83-830
Page 33 shows Mashka as the Russian equivalent of Mary.