Judul asli : "Filosofische Orientatie"
No Inv.: 13087-13091/P/Perp/94/5c~94-103/S/Perp/89/10c~478-479/S/Perp/90/2c~3091-3092/Pb/Perp/91/2c~3359-3368/P/Perp/92/10c~120884/PH/Perp/09/1c
No Inv.: 5921-5930/P/Perp/92/10c
No Inv.: 1756-1760/P/Perp/95/5c
Judul asli : "Pantheisme en Monisme"
No Inv.: 77424-77426/S/01/1c
No Inv.: 77696-77698/S/01/3c
Judul asli :"De tienduizend dingen"
No Inv.: 85582/S/Perp/03/1c~109391/S/Perp/07/1c