A. Abdollahi, Finitely generated soluble groups with an Engel condition on infinite subsets, Rend. Sem. Mat. Univ. Padova, 103 (2000) 47–49.
 A. Abdollahi and B. Taeri, A condition on finitely generated soluble groups, Comm. Algebra, 27 (1999) 5633–5638.
 C. Delizia, Finitely generated soluble groups with a condition on infinite subsets, Istit. Lombardo Accad. Sci. Lett. Rend. A, 128 (1994) 201–208.
 C. Delizia, On certain residually finite groups, Comm. Algebra, 24 (1996) 3531-3535.
 C. Delizia and C. Nicotera, Groups with conditions on infinite subsets, Ischia Group Theory 2006: Proceedings of a Conference in Honor of Akbar Rhmetulla, World Scientific Publishing, Singapore, 2007 46–55.
 C. Delizia, A. Rhemtulla and H. Smith, Locally graded groups with a nilpotency condition on infinite subsets, J. Austral. Math. Soc. Ser. A, 69 (2000) 415–420.
 J. D. Dixon, M. P. F. du Sautoy, A. Mann and D. Segal, Analytic pro-p-groups, London Math. Soc. Lecture Note Series, 157, Cambridge Univ. Press, Cambridge, 1991.
 A. Faramarzi Salles, Finitely generated soluble groups with a condition on infinite subsets, Bull. Aust. Math. Soc., 87 (2013) 152–157.
 Y. K. Kim and A. H. Rhemtulla, Weak maximality condition and polycyclic groups, Proc. Amer. Math. Soc., 123 (1995) 711–714.
 J. C. Lennox and J. Wiegold, Extensions of a problem of Paul Erdös on groups, J. Austral. Math. Soc. Ser. A, 31 (1981) 459–463.
 P. Longobardi, On locally graded groups with an Engel condition on infinite subsets, Arch. Math. (Basel), 76 (2001) 88–90.
 B. H. Neumann, A problem of Paul Erdös on groups, J. Austral. Math. Soc. Ser. A, 21 (1976) 467–472.
 D. J. Robinson, A course in the theory of groups, Second Edition, Springer-Verlag, Berlin, 1982.
 J. Tits, Free subgroups in linear groups, J. Algebra, 20 (1972) 250–270.