Rung-Ren Lin Wen-Hsiung Kuo Kun-Mao Chao Finding a Length-Constrained Maximum-Density Path in a Tree. 78-87 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2906&spage=78 2003 conf/isaac/2003 ISAAC db/conf/isaac/isaac2003.html#LinKC03