Paul Citroen, German-Dutch illustrator and educator (born 1896)

Roelof Paul Citroen was a German-born Dutch artist, art educator and co-founder of the New Art Academy in Amsterdam. Among his best-known works are the photo-montage Metropolis and the 1949 Dutch postage stamps.

March 13 is the 72nd day of the year in the Gregorian calendar; 293 days remain until the end of the year.