On Web sites
www.artfact.com and
www.artprice.com (something
www.findartinfo.com today, "buggy") mentions the German painter Max Blumenberg (1887 - 1969). Max Blumenberg This is obviously not very well known, because at international auctions had figured only one work "Sommertag an der Steilkuste" ( "Summer Day at the steep cliffs), cardboard /oil, 24h31 cm, dated to the 1930's. Try to find more information on the Internet. Good Luck!