Quasi-cyclic (QC) codes form an important generalization of cyclic codes. It is well know that QC codes of length sl with index s over the finite field F are F[y]-submodules of the ring F[x, y]/< x − 1, y − 1 >. The aim of the present paper, is to study QC codes of length sl with index s over the finite field F and find generator polynomials and generator matrix for these codes. To achieve this...