to Affine Group Schemes, W. C. Waterhouse (1979, ISBN 978-1-4612-6219-0) Local Fields, Jean-Pierre Serre (1979, ISBN 978-0-387-90424-5) Linear Operators
2015. ISBN 9781442252813. OCLC 985529980. Spring, Peter. Great Walls and Linear Barriers. Barnsley, South Yorkshire: Pen and Sword Books. 2015. ISBN 9781473853843