Hirotoshi Honma Shigeru Masuyama An Optimal Parallel Algorithm for Constructing a Spanning Forest on Trapezoid Graphs. 2296-2300 2008 91-A IEICE Transactions 9 http://dx.doi.org/10.1093/ietfec/e91-a.9.2296 db/journals/ieicet/ieicet91a.html#HonmaM08a