Empirical Study on the Determinants of Industrial Research and Development Expenditures. - Hirokazu Yamada (Int. J. Syst. Serv. Oriented Eng., 2017)

Japanese R&D Profitability: Industry Production Function Estimation Using Panel Data. - Hirokazu Yamada; Yuji Nakayama (Int. J. Syst. Serv. Oriented Eng., 2018)

Empirical Research on the Profitability of R&D Expenditure: Estimations Based on Firm-level Accounting Data in the Japanese Textile Industry. - Hirokazu Yamada; Yuji Nakayama (Int. J. Syst. Serv. Oriented Eng., 2019)

The Effects of R&D Expenditure and Technological Spillover on Industry Revenues in Japan. - Hirokazu Yamada (Int. J. Syst. Serv. Oriented Eng., 2020)

Homogenization of Japanese Industrial Technology From the Perspective of R&D Expenses. - Hirokazu Yamada (Int. J. Syst. Serv. Oriented Eng., 2021)

Identification methods and indicators of important patents. - Hirokazu Yamada (Libr. Hi Tech, 2022)

Japanese industrial technological structure based on the number of patent applications by technical field. - Hirokazu Yamada (Libr. Hi Tech, 2024)