Anita Saha Madhumangal Pal Tapan Kumar Pal An optimal parallel algorithm to construct a tree 3-spanner on interval graphs. 259-274 2005 82 Int. J. Comput. Math. 3 http://dx.doi.org/10.1080/00207160412331286851 db/journals/ijcm/ijcm82.html#SahaPP05