Definitions of critical thinking:
What is critical thinking?
https://www.gre.ac.uk/articles/ils/critical-thinking (University of Greenwich)
History of the concept:
Rutherford, A. (2018). Models For Critical Thinking: A Fundamental Guide to Effective Decision Making, Deep Analysis, Intelligent Reasoning, and Independent Thinking: 1, Independently Published.
Definitions of strategic thinking:
What is strategic thinking?
How to develop planning skills?
https://www.strath.ac.uk/professionalservices/careers/skills/generalskills/planningorganisingskills/ (University of Strathclyde Glasgow)