Peng Cheng Shigeru Masuyama Inequalities on the Number of Connected Spanning Subgraphs in a Multigraph. 178-186 2008 91-D IEICE Transactions 2 http://dx.doi.org/10.1093/ietisy/e91-d.2.178 db/journals/ieicet/ieicet91d.html#ChengM08