nemfrog: April 8th 1932, August 5th 1941, May 11th 1961 and other due dates. Source.  The date

nemfrog:

April 8th 1932, August 5th 1941, May 11th 1961 and other due dates. Source. 

The date due slip from “Animal forms; a text-book of zoology”
by Jordan, David Starr, 1851-1931; Heath, Harold, b. 1868
Publication date 1907, c1902