Shuji Ishida, Mikiko Nakagawa, Takao Fujino, Hidetoshi Yonemochi, Tetsunori Saikawa, Morio Ito,
Circadian variation of QT interval dispersion : Correlation with heart rate variability Journal of Electrocardiology. ,vol. 30, pp. 205- 210 ,(1997) ,
10.1016/S0022-0736(97)80005-2