Takamatsu, K., Y. Kozaki, K. Muarakami, K. Bannaka, K. Mitsunari, and Y. Nakata. “NEW ANALYSIS OF VISUALIZATION IN EDUINFORMATICS USING A NETWORK WITH PARAMETRIC AND NONPARAMETRIC CORRELATION COEFFICIENTS WITH THRESHOLD”. PEOPLE: International Journal of Social Sciences, vol. 4, no. 1, May 2018, pp. 619-30, doi:10.20319/pijss.2018.41.619630.