O.V. Borodin, A new proof of Grünbaum's 3-color theorem, Discrete Math. 169, 177-183, 1997.
August 28, 1997. Tommy R. Jensen
M.N. Ellingham and L. Goddyn, List edge colourings of some 1-factorable multigraphs, Combinatorica 16, 343-352, 1996.
August 7, 1997. Tommy R. Jensen
C. Thomassen, Grötzsch's 3-Color Theorem and its Counterparts for the Torus and the Projective Plane, J. Combin. Theory Ser. B 62, 268-279, 1994.
August 13, 1997. Tommy R. Jensen