Budaghyan, L. E. 2003. “ON FORMALIZATION  OF  NOTION  OF  $\delta$-REDUCTION  IN MONOTONIC  MODELS  OF  TYPED  $\lambda$-CALCULUS”. Proceedings of the YSU A: Physical and Mathematical Sciences 37 (1 (200): 27-36. https://doi.org/10.46991/PYSUA.2003.37.1.027.