Bottom-up discovery of frequent rooted unordered subtrees.

Yijun Bei Gang Chen Lidan Shou Xiaoyan Li Jinxiang Dong Bottom-up discovery of frequent rooted unordered subtrees. 70-88 2009 179 Inf. Sci. 1-2 http://dx.doi.org/10.1016/j.ins.2008.08.020 db/journals/isci/isci179.html#BeiCSLD09