No Inv.: 113/P/Perp/95/1c~84341/P/Perp/02/1c
No Inv.: 11025/Perp/62/1c~11006-11007/Perp/62/2c~11032/Perp/62/1c
Judul asli : "Element of Philosophy"
No Inv.: 291-293/S/Perp/96/3c
Judul asli : "De Wijsbegeerte van de 20e Eeuw"
No Inv.: 7299-7303/P/Perp/92/5c
Judul asli : "Inleiding tot de Wetenschapsleer"
No Inv.: 102907/S/Perp/05/1c