Masataka Takamura Tom Altman Yoshihide Igarashi Speedup of Vidyasankar's algorithm for the group. 85-91 2004 91 Inf. Process. Lett. 2 http://dx.doi.org/10.1016/j.ipl.2004.03.012 db/journals/ipl/ipl91.html#TakamuraAI04