HNN-расширения

Sapir, Mark; Wise, Daniel T. Ascending HNN extensions of residually finite groups can be non-Hopfian and can have very few finite quotients.
    J. Pure Appl. Algebra 166, No.1-2, 191-202 (2002). [ISSN 0022-4049]

Geoghegan, Ross; Mihalik, Michael L.; Sapir, Mark; Wise, Daniel T. Ascending HNN extensions of finitely generated free groups are Hopfian.
    Bull. Lond. Math. Soc. 33, No.3, 292-298 (2001). [ISSN 0024-6093]

Andreadakis, S.; Raptis, E.; Varsos, D. Hopficity of certain HNN-extensions.
    Comm. Algebra, v.20, No.5, 1511-1533 (1992).

Andreadakis, S.; Raptis, E.; Varsos, D. Residual finiteness and Hopficity of certain HNN extensions.
    Arch. Math. 47, 1-5 (1986).

[A] Meter, David. Non-hopfian groups.
    J. London Math. Soc. 26, No.2, 265–270 (1982).

Группы с одним определяющим соотношением

[A] Raptis, E.; Talelli, O.; Varsos, D. On the Hopficity of certain HNN-extensions with base a Baumslag-Solitar group.
    Algebra Colloq. 9, No.1, 39-48 (2002). [ISSN 1005-3867; ISSN 0219-1733]

[A] Witbooi, Peter Finite images of groups.
    Quaest. Math. 23, No.3, 279-285 (2000). ISSN{1607-3606}

[A] Anhel, Michael. The endomorphisms of certain one-relator groups and the generalized Hopfian Problem.
    Bul. Amer. Math. Soc. 77, No.3, 348–350 (1971).

Свободные и разрешимые группы

Grunewald, F.J.; Pickel, P.F.; Segal, P. Polycyclic groups with isomorphic finite quotients.
    Ann. Math. 111, No.1, 155–195 (1980).

[A] Baumslag, G. Residually finite groups with the same finite images.
    Compos. Math. 29, No.3, 249–252 (1974).

Прочее

[A] Deo, S.; Sankaran, P.; Varadarajan, K. Some finiteness properties of groups and their automorphism groups.
    Algebra Colloq. 7, No.4, 411-424 (2000). [ISSN 1005-3867; ISSN 0219-1733]