2 citations to https://www.mathnet.ru/rus/smj7545

1. V. S. Atabekyan, V. H. Mikaelian, “On Benign Subgroups Constructed by Higman's Sequence Building Operation”, J. Contemp. Mathemat. Anal., 59:1 (2024), 1  
2. Vahagn H. Mikaelian, “The Higman operations and embeddings of recursive groups”, Journal of Group Theory, 2023