Jan Woltjer was born in 1849.
Jan Woltjer - astronomer - was born in 1891.
Jan Woltjer died in 1917.
Jan Woltjer - astronomer - died in 1946.
Lodewijk Woltjer was born in 1930.
Janus Woltjer has written: 'Lucretii Philosophia cum fontibus comparata'
Jan Hanford was born in 1953.
Jan Harrison was born in 1944.
Jan Smit was born on December 31, 1985.
Jan Huyghebaert was born in 1945.
Jan Bruins was born in 1940.
Jan Goossens was born on 1958-12-18.
Jan Rychlík was born in 1916.