Here, I want to point out some sources about oxidation number and its story.
1. G. Parkin, J. Chem. Educ. 2006, 83, 791. This paper tells about the differences between oxidation numbers, formal charge, and numbers.
2. D. Steinborn, Journal of Chemical Education 81 (8), 2004, 1148-54. It is about arbitrariness of oxidation numbers
