Radkova, Diana, and Asen Bojilov. 2008. “Cyclic Codes With Lenght Divisible by the Field Characteristic As Invariant Subspaces”. Ann. Sofia Univ. Fac. Math. And Inf. 98 (December):181-89. https://stipendii.uni-sofia.bg/index.php/fmi/article/view/137.