I have, since the creation of this blog, referred to myself in my profile as a "philomath", which means "lover of knowledge".
Never. Stop. Learning.
For this, the below sites have been extremely useful. Its always beneficial to stretch your understanding of things, and to compare and contrast how similar tools are used to engage extremely disparate problems. The history of Finance and Economics can accurately be described in the same fashion...a history of the conflict of mechanisms.
MIT (open source)
Stanford (open source)