Jan Woltjer died in 1917.
Jan Woltjer - astronomer - died in 1946.
Jan Woltjer was born in 1849.
Jan Woltjer - astronomer - was born in 1891.
Lodewijk Woltjer was born in 1930.
Janus Woltjer has written: 'Lucretii Philosophia cum fontibus comparata'
Jan Steen died in 1679.
Jan Vostrcil died in 1985.
Jan Fifka died in 1970.
Jan Grmela died in 1957.
Jan Zelenka died in 1931.
Jan Rypka died in 1968.
Jan Sierada died in 1943.