1. J.D. Adler, M. Garlow and E.R. Wheland, Groups of order p4 made less difficult, preprint, arXiv:1611.00461v1.
2. L. An and Q. Zhang, Finite metahamiltonian p-groups, J. Algebra, 442 (2015), 23–35.
3. De Gruyter Exp. Math.;Y Berkovich,2008
4. M. Brescia, M. Ferrara and M. Trombetti, Groups whose subgroups are either abelian or pronormal, Kyoto J. Math., to appear.
5. M. Brescia and M. Trombetti, Locally finite simple groups whose non-abelian subgroups are pronormal, to appear.