\begin{thebibliography}{Wri73b} \bibitem[CH67]{CH} R.~W. Carter and T.~O. Hawkes. \newblock The {$\F$}-normalizers of a finite soluble group. \newblock {\em J. Alg.}, 5:175 -- 201, 1967. \bibitem[DH92]{DH} K.~Doerk and T.~O. Hawkes. \newblock {\em Finite soluble groups}. \newblock Walter de Gruyter, 1992. \bibitem[EW]{EW} B.~Eick and C.~R.~B. Wright. \newblock Computing subgroups by exhibition in finite solvable groups. \newblock To appear in J. Symbolic Comp. \bibitem[Gas63]{G} W.~Gasch\"utz. \newblock Zur theorie der endlichen aufl\"osbaren gruppen. \newblock {\em Math. Z.}, 80:300 -- 305, 1963. \bibitem[Wri73a]{WA} C.~R.~B. Wright. \newblock An internal approach to covering groups. \newblock {\em J. Alg.}, 25:128 -- 145, 1973. \bibitem[Wri73b]{WB} C.~R.~B. Wright. \newblock On internal formation theory. \newblock {\em Math. Z.}, 134:1 -- 9, 1973. \end{thebibliography}