Friedrichs, Gordon M. Max Planck Institute for Comparative Public Law and International Law, Max Planck Society;
https://www.taylorfrancis.com/chapters/edit/10.4324/9781003139850-24/quantitative-content-analysis-gordon-friedrichs?context=ubx&refId=ce301b82-454b-45af-8a78-bae6e97261ec (出版社版)