1. 1) M. KAWAKAMI and K. FURUKAWA: Potential difference between two kinds of metals, Nihon-no-shikai, 240.
2. 2) T. KOBAYASHI: Potential difference between heterogeneous metals used for oral fillings (a speech delivered at 12 th Meeting of Japan Oral Pathological Society).
3. 3) T. IKESHITA: Hygienic and metallurgic study on the galvanic function between hetero geneous metals for dental use, Shikagaku-Zasshi Vol.8, 4, 5 and 6.
4. 4) K. SHINDAI: Clinical cases of nickel-chrome alloy, Nihon-no-shikai, 240.
5. 5) S. IWAO and N. SHIGETA: Investigation regarding copper alloy for dental use (a speech delivered at 6 th Meeting of Japan Dental Materials and Apparatus Society), May, 1954.