1. Research Report No. 683003, Central Research Institute of Electrical Power Industry (CRIEPI), 1983.
2. , and . Proceedings of 1983 National Conference, I.E.E., Japan, No. 167.
3. and . Proceedings of 1983 Tokyo Area Conference, I.E.E., Japan, No. 82.
4. , , and . Proceedings of 1982 National Conference, I.E.E., Japan, No. 1140.
5. , , and . Proceedings of 1983 National Conference, I.E.E., Japan, No. 1041.