1971  Sureśvara’s Taittirīyopaniṣadbhāṣyavārtikam, transl. into English with an introd. and notes , Leiden: Brill, 1971. X, 214 pp. – PhD thesis Utrecht; has also appeared as Orientalia Rheno-Traiectina 12.
1973  “Hindoeïstische Wijsbegeerte.” In: Kwee Swan Liat et al., Oosterse filosofie, Assen, pp. 15-26
1974  “Indische logica.” Amersfoortse stemmen 55: 9-14.