Bergeron, Bryan P. (1998, August). Optical mark recognition. Postgraduate Medicine online. Retrieved June 7, 2006 from 存档副本. [2006-06-13]. (原始内容存档于2006-06-13).
Bergeron, Bryan P. (1998, August). Optical mark recognition. Postgraduate Medicine online. Retrieved June 7, 2006 from 存档副本. [2006-06-13]. (原始内容存档于2006-06-13).