1. Axenovich, M.A.: On multiple coverings of the infinite rectangular grid with balls of constant radius. Disc. Math. 268(1), 31–48 (2003)
2. Leibniz International Proceedings in Informatics (LIPIcs);A Ballier,2008
3. Springer Monographs in Mathematics;T Ceccherini-Silberstein,2010
4. Geravker, N., Puzynina, S.A.: Abelian Nivat’s conjecture for non-rectangular patterns (2021). arXiv:2111.04690
5. Heikkilä, E.: Algebrallinen näkökulma peittokoodeihin. Master’s thesis University of Turku (2020)