1. Takenaka , A. and Fukuoka , T. 1983a . “Mechanical Seal” . United States Patent No. 4,407,513
2. Takenaka , A. and Fukuoka , T. 1983b . “Mechanical Seal” . United States Patent No. 4,415,168.
3. Takenaka , A. and Fukuoka , T. 1983c . “Mechanical Seal” . United States Patent No. 4,420,163.
4. A New Concept of Zero-Leakage Noncontacting Mechanical Face Seal
5. A Zero-Leakage Film Riding Face Seal