Funding for this research was provided by:
Japan Society for the Promotion of Science (JP 17H06086)
Article History
Received: 19 September 2018
Accepted: 29 November 2019
First Online: 30 December 2019
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board, Institute for Economic Studies, Keio University (Reference number 15002).
: Not applicable.
: The authors declare that they have no competing interests.