 Otsuki, S. 

 Otsuki, S. (H. Arimura, T. Shinohara and S. Otsuki)  A polynomial time algorithm for finding finite unions of tree pattern languages  1993 
 Otsuki, S. (H. Arimura, T. Shinohara and S. Otsuki)  Finding Minimal Generalizations for Unions of Pattern Languages and Its Application to Inductive Inference from Positive Data  1994 
 Otsuki, S. (H. Arimura, T. Shinohara and S. Otsuki)  Polynomial time inference of unions of tree pattern languages  1992 
