an Entity references as follows:
Laurens Bogtman (8 February 1900 in Oudkarspel – 1969 in Hilversum, the Netherlands) was a Dutch baritone. Unlike many contemporary singers his career began late, at the age of 30, and he studied singing in Berlin, with Otto Iro in Vienna and with Aaltje Noordewier-Reddingius in Hilversum. Bogtmam debuted in 1932 in a concert with the Kölner Bachverein (Cologne Bach Society). He then had a successful career as an oratorio singer in Germany, Austria and England and travelled further afield.