In papers by Castagnoli et al. and Van Lint, cyclic codes with repeated roots are analyzed. Both papers fail to acknowledge a previous work by Chen, dating back to 1969, which includes an analysis of even, length binary cyclic codes. Results from Chen’s study are presented.
Morelos-Zaragoza, Robert H., "A Note on Repeated-Root Cyclic Codes" (1991). Faculty Publications. Paper 3.