On Perfect Lee Codes
In this paper we survey recent results on the Golomb–Welch conjecture and its generalizations and variations. We also show that there are no perfect 2-error correcting Lee codes of block length 5 and 6 over Z. This provides additional support for the Golomb Welch conjecture as it settles the two smallest cases open so far.
Horak, Peter, "On Perfect Lee Codes" (2009). SIAS Faculty Publications. 149.