Stephen Gang Wu Forrest Sheng Bao Eric You Xu Yuxuan Wang Yi-Fan Chang Qiao-Liang Xiang A Leaf Recognition Algorithm for Plant Classification Using Probabilistic Neural Network http://arxiv.org/abs/0707.4289 2007 CoRR abs/0707.4289 db/journals/corr/corr0707.html#abs-0707-4289 informal publication