Irreducible cyclic codes of length 4pn and 8pn

Further factorization of x − 1 over a finite field

“…Applying this result, they presented a general idea to factorize cyclotomic polynomials over finite fields. Some explicit factorizations of certain cyclotomic polynomials or Dickson polynomials can be found in [1,2,3,4,5,6,7,11,12], etc.…”