CT-1990-09: de Vrijer, Roel (1990) Unique Normal Forms for Combinatory Logic with Parallel Conditional, a case study in Conditional Rewriting. [Report]
ML-1989-02: de Vrijer, Roel (1989) Extending the Lambda Calculus with Surjective Pairing is conservative. [Report]
ITLI-1987-03: Klop, Jan Willem and de Vrijer, Roel (1987) Unique Normal Forms for Lambda Calculus with Surjective Pairing. [Report]
HDS-30: de Vrijer, Roel (2019) Surjective pairing and strong normalization: two themes in lambda calculus. Doctoral thesis, University of Amsterdam.