[1] T. Abualrub and I. Siap, Reversible cyclic codes over $Z_4$, Australas. J. Comb. 38 (2007), 195–206.
[2] M. Ashraf and G. Mohammad, $(1 + u)$-constacyclic codes over ${Z}_4 + u{Z}_4$, arXiv:1504.03445v1. (2015).
[5] Y. Cengellenmis, A. Dertli, and N. Aydın, Some constacyclic codes over ${Z}_4[u]/⟨u^2⟩$, new Gray maps, and new quaternary codes, Algebra Colloq. 25 (2018), no. 3, 369–376.
https://doi.org/10.1142/S1005386718000263
[6] J. Gao, F. Ma, and F. Fu, Skew constacyclic codes over the ring $F_q + vF_q$, Appl. Comput. Math 6 (2017), no. 3, 286–295.
[9] H. Islam and O. Prakash, A class of constacyclic codes over the ring $Z_4[u, v]/⟨u^2, v^2, uv -vu⟩$ and their Gray images, Filomat 33 (2019), no. 8, 2237–2248.
[10] E. Martinez-Moro, S. Szabo, and B. Yildiz, Linear codes over $Z_4[x]/⟨x^2 + 2x⟩$, Int. J. Inf. Coding Theory 3 (2015), no. 1, 78–96.
[12] M. Özen, F.Z. Uzekmek, N. Aydin, and N. Özzaim, Cyclic and some constacyclic codes over the ring $Z_4[u]/⟨u^2-1⟩$, Finite Fields Appl. 38 (2016), 27–39.
[13] V.S. Pless and Z. Qian, Cyclic codes and quadratic residue codes over $Z_4$, IEEE Trans. Inform. Theory 42 (1996), no. 5, 1594–1600.
https://doi.org/10.1109/18.532906
[14] M. Shi, L. Qian, L. Sok, N. Aydin, and P. Solé, On constacyclic codes over $Z_4[u]/⟨u^2-1⟩$ and their Gray images, Finite Fields Appl. 45 (2017), 86–95.
[16] T. Yao, M. Shi, and P. Solé, Skew cyclic codes over $F_q + uF_q + vF_q + uvF_q$, J. Algebra Comb. Discrete Struct. Appl. 2 (2015), no. 3, 163–168.
[18] B. Yildiz and A. Kaya, Self-dual codes over $Z_4[x]/⟨x^2+2x⟩$ and the $Z_4$-images, Int. J. Inf. Coding Theory 5 (2018), no. 2, 142–154.
[19] H. Yu, Y. Wang, and M. Shi, $(1+u)$-constacyclic codes over $Z_4+uZ_4$, Springerplus 5 (2016), no. 1, Artice number 1325.