A. Arikan and H. Smith (2011). On groups with all proper
subgroups of finite exponent. J. Group Theory. 14, 765-775 A. O. Asar (2000). Locally nilpotent $p$-groups whose proper subgroups are hypercentral or nilpotent-by-Chernikov. J. London Math. Soc. (2). 61, 412-422 A. O. Asar (2011). Totally imprimitive permutation groups with the cyclic-block property. J. Group Theory. 14, 127-141 A. O. Asar (2014). On infinitely generated groups whose proper subgroups are solvable. J. Algebra. 399, 870-886 G. Endimioni and G. Traustason (2001). On torsion-by-nilpotent groups. J. Algebra. 241, 669-676 D. Gorenstein (1968). Finite Groups. Harper \& Row, Publishers, New York-London. B. Huppert (1967). Endliche Gruppen I. Springer-Verlag, Berlin, Heidelberg, New York. B. Huppert and N. Blackburn (1982). Finite Groups II. Springer-Verlag, Berlin, Heidelberg, New York. O. H. Kegel and B. A. F. Wehrfritz (1973). Locally Finite Groups. North-Holland Publishing Co., Amsterdam-London, American Elsevier Publishing Co., Inc., New York. J. C. Lennox and D. J. S. Robinson (2004). The Theory of Infinite Soluble Groups. The Clarendon Press, Oxford University Press, Oxford. V. D. Mazurov and E. I. Khukhro (2014). Unsolved Problems in Group Theory. (The Kourovka Notebook), Russian Academy of Sciences, Siberian Division, Novosibirsk. D. J. S. Robinson (1972). Finiteness Conditions and Generalized Solvable Groups Part I, II. Springer, New York. D. J. S. Robinson (1980). A Course in the Theory of Groups. Springer-Verlag, New York, Heidelberg, Berlin. P. Shumyatsky (2003). On extensions of groups of finite exponent. Glasg. Math. J.. 45, 535-538