1. Endo, M., Kobayashi, S., Suzuki, H., Takemoto, T., and Nakayama, K.: Diagnosis of early esophageal cancer. Endoscopy, 3: 61, 1971.
2. Endo, M., Nakayama, K., Sato, H., Akiyama, Y., Hanyu, F., Kakegawa, T., Nabeya, K., and Takahashi, H,: Endoscopy of esophageal cancer (Japanese). Gastroenterological Endoscopy, 13:417, 1971.
3. Suzuki, H., Kobayashi, S., Endo, M., and Nakayama, K.: Diagnosis of early esophageal cancer. Surgery, 71: 99, 1972.