FFour-colour ProblemFour-colour Problemde Oystein OreEdiciones (1)Four-colour Problem (1967)Academic Press Inc.,U.S. · ISBN 9780125281508Más obras de Oystein OreIInvitation to Number TheoryInvitation to Number TheoryCCardano, the gambling scholarCardano, the gambling scholarTheory of graphs (American Mathematical Society. Colloquium publications)