Kazutake Kawai Dai Yamamoto Tomoyuki Kato Jun Takafuji. A Study of the Relative Age Effects of Junior Soccer Players :When Does the Relative Age Effects Start in School Year?. Football Science. 2018. 15. 52-60
Jun Takafuji, Tomoyuki Kato, Dai Yamamoto, Kazutake Kawai. A Study of Relative Age Effects on Junior Soccer Players: A Comparison between Germany, Spain, and Japan for Players Aged 12 or Younger. 体育・スポーツ科学. 2018. 27. 1-10
The development of a computerised notational analysis system for soccer allowing accurate reproduction of plays and feedback effects.
(SECOND WORLD CONGRESS of NOTATIONAL ANALYSIS of SPORT (Wales,Cardiff) 1994)