%0 Journal Article %T Hamiltonian Cycles in the Square of a Graph %A Jan Ekstein %J Mathematics %D 2012 %I arXiv %X We show that under certain conditions the square of the graph obtained by identifying a vertex in two graphs with hamiltonian square is also hamiltonian. Using this result, we prove necessary and sufficient conditions for hamiltonicity of the square of a connected graph such that every vertex of degree at least three in a block graph corresponds to a cut vertex and any two these vertices are at distance at least four. %U http://arxiv.org/abs/1206.4846v1