The smallest hard-to-color graph. - Pierre Hansen; Julio Kuplinsky (Discret. Math., 1991)

Bounded vertex colorings of graphs. - Pierre Hansen; Alain Hertz; Julio Kuplinsky (Discret. Math., 1993)

Mixed graph colorings. - Pierre Hansen; Julio Kuplinsky; Dominique de Werra (Math. Methods Oper. Res., 1997)

A Union of Proper Subspaces?: 10707. - John Isbell; Julio Kuplinsky; Leon Mattics (Am. Math. Mon., 2000)

A Family of Polynomials: 10989. - Roland Bacher; Julio Kuplinsky; Richard Stong (Am. Math. Mon., 2004)

Enumeration of Permutations by Disorder: 10975. - Emeric Deutsch; Julio Kuplinsky; Tina Garrett (Am. Math. Mon., 2004)