About the Authors
School of Library and Information Science, Keio University, Tokyo, Japan
Kunitachi College of Music Library, Tokyo, Japan
Tokyo Institute of Technology Library, Tokyo, Japan
Faculty of Library, Information and Media Studies, University of Tsukuba, Ibaraki, Japan
The authors have declared that no competing interests exist.
Conceived and designed the experiments: KK. Performed the experiments: KK TM KY. Analyzed the data: KK MM. Wrote the paper: KK MM.