Regular and normal closure operators and categorical compactness for groups. - Temple H. Fay; Gary L. Walls (Appl. Categorical Struct., 1995)

On the Group of Automorphisms of a Group. - Marian Deaconescu; Gary L. Walls (Am. Math. Mon., 2011)

Subgroup Perfect Codes in Cayley Graphs. - Xuanlong Ma; Gary L. Walls; Kaishun Wang; Sanming Zhou (SIAM J. Discret. Math., 2020)