• Explaining Declining Business Dynamism: A Monetary Growth-Theoretic Approach (with Tat-kei Lai and Sumiko Niwa), RIETI Discussion Paper Series 21-E-058, July 2021. 

• Economic Black Holes and Labor Singularities in the Presence of Self-replicating Artificial Intelligence  (with Makoto Yano), RIETI Discussion Paper Series 19-E-062, 2019. 

• Two-dimensional Constrained Chaos and Time in Innovation: An Analysis of Industrial Revolution Cycles (with  Makoto Yano), RIETI Discussion Paper Series 19-E-008, February 2019. (The previous version appeared as MQ Discussions Series 2013-11.) 

Related studies include:

• Love of Novelty: A Source of Innovation-Based Growth... or Underdevelopment Traps? (with Tat-kei Lai and Kenji Sato), MPRA Paper No. 92915, March 2019. 

Related studies include: 

• Can Trade Unions Increase Social Welfare? An R&D Model with Cash-in-Advance Constraints (with António Neto and Ana Paula Ribeiro), MPRA Paper 77312, March 2017. 

• A Simple Theory of Offshoring and Reshoring (with Angus C. Chu and Guido Cozzi), MPRA Paper 44557, February 2013. 

• Technological Change and International Interaction in Environmental Policies (with Yasuhiro Takarada), MPRA Paper 55653, January 2013.  

• A Theory of Innovation through Global Collaboration and Wage Inequality, CUIE Paper 0905, 2010. (Unpublished Appendix)