Ronri Sugaku by Saburo Tamura (4768700985 9784768700983 4-7687-0098-5)
Juryoku to Rikigakuteki Sekai: Koten to Shite No Koten Rikigaku by Yoshitaka Yamamoto (4768701086 9784768701089 4-7687-0108-6)
