1. Jennifer D. Key and Johannes Siemons, Closure properties of the special linear groups, Ars Combin. 22 (1986), 107–117.[MR]
  2. Jennifer D. Key and Johannes Siemons, On the k-closure of finite linear groups, Boll. Un. Mat. Ital. B (7) 1 (1987), no. 1, 31–55.[MR]
  3. Jennifer D. Key and Johannes Siemons, Regular sets and geometric groups, Results Math. 11 (1987), no. 1-2, 97–116.[MR]
  4. Jennifer D. Key, Johannes Siemons, and Ascher Wagner, Regular sets on the projective line, J. Geom. 27 (1986), no. 2, 188–194.[MR]