I found just a few more bits to add to the information about Bozart. A 1920 publication of the Dry Goods Economist listed Blouses and Waists manufacturers and among the listings is:
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A label on a blouse sold on Etsy is clearly the same Bozart trademark as yours, but has the Helitzer attribution:
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This 1945 ad obviously indicates Bozart Co. is a Helitzer Bros., Inc. business:
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This 1949 publication lists the Helitzer partners in the Bozart company:
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I saw a 1961 reference to a Melvin Helitzer as an officer(?) or director(?) of Bozart, so I am assuming the Helitzer family was or is the owner of, or partners in, Bozart.