K. Ushio
发表
K. Ushio,
S. Tazawa,
Sumiyasu Yamamoto,
1978
.
N. Hamada,
K. Ushio,
Sumiyasu Yamamoto,
1975
.
Kazuhiko Ushio,
Shinsei Tazawa,
Sumiyasu Yamamoto,
1977
.
Kazuhiko Ushio,
Yoshikazu Ohtsubo,
K. Ushio,
2000,
Discret. Math..