Addendum to: The structures of groups of order \(2^ 3p^ 2\) (Q1080946)

In his paper mentioned in the title [ibid. 4, 77-93 (1983; Zbl 0511.20017)] \textit{Y. Zhang} classified the groups of order \(2^ 3p^ 2\) where p is a prime different from 3 and 7. Since any such group has a normal Sylow p-subgroup, the present author remarks that Zhang's argument goes through when \(p=7\) also in case the Sylow 7-subgroup is normal so that there are 42 groups of order \(2^ 37^ 2\) with normal Sylow 7- subgroup and proves that there are exactly two groups of order \(2^ 37^ 2\) without normal Sylow 7-subgroup; thus there are 44 groups of order \(2^ 37^ 2\). \(\{\) Correction: On line 15 of page 384 the second matrix must read \[ \left[\begin{matrix} 0&0&1 \\ 1&0&0 \\ 0&1&1 \end{matrix}\right] \text{ instead of } \left[\begin{matrix} 0&0&1 \\ 1&0&1 \\ &0&1&0 \end{matrix}\right]. \]