1. Jacobus Cornelius Kapteyn : born investigator of the heavens /: born investigator of the heavens. ([2015]) Authors: Kruit, Pieter C. van der Record Type: Book Extent: 1 online resource, illustrations View Content: Available online (eLD content is only available in our Reading Rooms) ↗
2. Jan Hendrik Oort : master of the galactic system /: master of the galactic system. ([2019]) Authors: Kruit, Pieter C. van der Record Type: Book Extent: 1 online resource View Content: Available online (eLD content is only available in our Reading Rooms) ↗
3. Willem de Sitter : Einstein's friend and opponent /: Einstein's friend and opponent. ([2018]) Authors: Guichelaar, Jan, 1945- Record Type: Book Extent: 1 online resource View Content: Available online (eLD content is only available in our Reading Rooms) ↗