On Rational phase-Locking oscillations of a Simple Sawtooth oscillator with Ujt. - Yoshitaka Hasegawa; Ryuichiro Tanaka; Yoshisuke Ueda (Int. J. Bifurc. Chaos, 2001)

Tangled Separatrices on Two Degrees of Freedom swing equation System. - Yoshitaka Hasegawa; Yoshisuke Ueda (Int. J. Bifurc. Chaos, 2001)

Oscillational Responses and Basin Structure on One-Well quintic Potential. - Yoshitaka Hasegawa (Int. J. Bifurc. Chaos, 2002)