A new paper has been published by Takakura et al.
Yuriko Takakura, Masanori Nakayama, Issei Fujishiro: “Visual Analysis for the Compositional Process of Composers in Spectral
School”, IIEEJ Transactions on Image Electronics and Visual Computing, Vol. 6, No. 1, pp. 22-30, 2018.
You can find the journal website here (in Japanese).