B. Amberg, S. Franciosi and F. de Giovanni (1992). Products of groups. Oxford Mathematical Monographs, The Clarendon Press, Oxford University Press, New York. B. Bruno and R. E. Phillips (1981). Groups with restricted non-normal subgroups. Math. Z.. 176 (2), 199-221 M. R. Celentani and U. Dardano (1993). Groups whose infinite proper subgroups are $T$-groups. Note Mat.. 13 (2), 295-307 S. N. \v Cernikov (1971). Infinite nonabelian groups in which all infinite nonabelian subgroups are invariant. Ukrain. Math. J.. 23, 498-517 M. De Falco, F. de Giovanni and C. Musella (2007). Groups whose non-normal subgroups have small commutator subgroup. Algebra Discrete Math.. (3), 46-58 M. De Falco, F. de Giovanni and C. Musella (2008). The Schur property for subgroup lattices of groups. Arch. Math. (Basel). 91 (2), 97-105 M. De Falco, F. de Giovanni and C. Musella (2009). Groups whose finite homomorphic images are metahamiltonian. Comm. Algebra. 37 (7), 2468-2476 M. De Falco, F. de Giovanni and C. Musella On a class of metahamiltonian groups. Ricerche Mat., to appear.. M. De Falco, F. de Giovanni, C. Musella and R. Schmidt (2003). Groups in which every non-abelian subgroup is permutable. Rend. Circ. Mat. Palermo (2). 52 (1), 70-76 M. De Falco, F. de Giovanni, C. Musella and R. Schmidt (2003). Groups with metamodular subgroup lattice. Colloq. Math.. 95 (2), 231-240 M. De Falco, F. de Giovanni, C. Musella and Y. P. Sysak (2003). Periodic groups with nearly modular subgroup lattice. Illinois J. Math.. 47 (1-2), 189-205 M. De Falco, F. de Giovanni, C. Musella and Y. P. Sysak (2007). Groups with normality conditions for non-abelian subgroups. J. Algebra. 315 (2), 665-682 M. De Falco, F. de Giovanni, C. Musella and Y. P. Sysak On metahamiltonian groups of infinite rank. to appear.. M. De Falco, F. de Giovanni, C. Musella and N. Trabelsi Groups with restrictions on subgroups of infinite rank. Rev. Mat. Iberoam., to appear.. F. De Mari and F. de Giovanni (2005). Groups with few normalizer subgroups. Irish Math. Soc. Bull.. 56, 103-113 F. De Mari and F. de Giovanni (2006). Groups with finitely many normalizers of non-abelian subgroups. Ric. Mat.. 55 (2), 311-317 M. R. Dixon, M. J. Evans and H. Smith (1999). Groups with all proper subgroups (finite rank)-by-nilpotent. Arch. Math. (Basel). 72, 321-327 I. I. Eremin (1959). Groups with finite classes of conjugate abelian subgroups. Mat. Sb. (N.S.). 47, 45-54 M. J. Evans and Y. Kim (2004). On groups in which every subgroup of infinite rank is subnormal of bounded defect. Comm. Algebra. 32, 2547-2557 F. de Giovanni, C. Musella and Y. P. Sysak (2001). Groups with almost modular subgroup lattice. J. Algebra. 243 (2), 738-764 L. A. Kurdachenko, J. Otal, A. Russo and G. Vincenzi (2004). Groups whose non-normal subgroups have finite conjugacy classes. Math. Proc. R. Ir. Acad.. 104A (2), 177-189 L. A. Kurdachenko, J. Otal and I. Subbotin (2002). Groups with prescribed quotient groups and associate module theory. World Scientific, Singapore. N. F. Kuzennyi, S. S. Levishchenko and N. N. Semko (1988). Groups with invariant infinite non-abelian subgroups. Ukrain. Math. J.. 40 (3), 267-273 N. F. Kuzennyi and N. N. Semko (1983). Structure of solvable nonnilpotent metahamiltonian groups. Math. Notes. 34 (2), 572-577 N. F. Kuzennyi and N. N. Semko (1984). On the structure of infinite nilpotent periodic metahamiltonian groups. in Structure of groups and their subgroup characterization, Kiev. , 101-111 N. F. Kuzennyi and N. N. Semko (1985). Structure of solvable metahamiltonian groups. Dokl. Akad. Nauk Ukrain. SSR Ser. A. (2), 6-9 N. F. Kuzennyi and N. N. Semko (1986). On the structure of nonperiodic metahamiltonian groups. Izv. Vuzov Matematika. 11, 32-38 N. F. Kuzennyi and N. N. Semko (1987). Structure of periodic metabelian metahamiltonian groups with a nonelementary commutator subgroup. Ukrain. Math. J.. 39 (2), 149-153 N. F. Kuzennyi and N. N. Semko (1988). The structure of periodic metabelian metahamiltonian groups with an elementary commutator subgroup of rank two. Ukrain. Math. J.. 40 (6), 627-633 N. F. Kuzennyi and N. N. Semko (1989). Structure of periodic nonabelian metahamiltonian groups with an elementary commutator subgroup of rank three. Ukrain. Math. J.. 41 (2), 153-158 N. F. Kuzennyi and N. N. Semko (1990). Metahamiltonian groups with elementary commutator subgroup of rank two. Ukrain. Math. J.. 42 (2), 149-154 J. C. Lennox (1973). Finite Frattini factors in finitely generated soluble groups. Proc. Amer. Math. Soc.. 41, 356-360 A. A. Mahnev (1976). On finite metahamiltonian groups. Ural. Gos. Univ. Mat. Zap.. 10 (1), 60-75 B. H. Neumann (1955). Groups with finite classes of conjugate subgroups. Math. Z.. 63, 76-96 R. E. Phillips and J. S. Wilson (1978). On certain minimal conditions for infinite groups. J. Algebra. 51 (1), 41-68 Y. D. Polovicki\u{\i} (1980). Groups with finite classes of conjugate infinite abelian subgroups. Soviet Math. (Iz. VUZ). 24, 52-59 D. J. S. Robinson (1968). Residual properties of some classes of infinite soluble groups. Proc. London Math. Soc. (3). 18, 495-520 D. J. S. Robinson (1972). Finiteness conditions and generalized soluble groups. Springer, Berlin. G. M. Romalis and N. F. Sesekin (1966). Metahamiltonian groups. Ural. Gos. Univ. Mat. Zap.. 5, 101-106 G. M. Romalis and N. F. Sesekin (1968). Metahamiltonian groups II. Ural. Gos. Univ. Mat. Zap.. 6, 52-58 G. M. Romalis and N. F. Sesekin (1969/70). Metahamiltonian groups III. Ural. Gos. Univ. Mat. Zap.. 7, 195-199 R. Schmidt (1994). Subgroup lattices of groups. de Gruyter, Berlin. N. N. Semko and O. A. Yarovaya (2009). On some generalization of metahamiltonian groups. Algebra Discrete Math.. (2), 70-78 G. Zacher (1980). Una caratterizzazione reticolare della finitezza dell'indice di un sottogruppo in un gruppo. Atti Accad. Naz. Lincei Rend. Cl. Sci. Fis. Mat. Natur. (8). 69 (6), 317-323
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