Overview of articles, books and videos.
Graham Berrisford made a good reference page: A new look at Systems Thinking
A short youtube movie about what is Systems Thinking? What is a part, and what is the whole?
A good starting point to get an overview of all material about Systems Thinking is the contribution of Niamat Ullah Ibne Hossain, Vidanelage L. Dayarathna, Morteza Nagahi and Raed Jaradat with the article: Systems Thinking: A Review and Bibliometric Analysis.