Aside from sources directly mentioned throughout the site, these are the main resources I used to gain a decent understanding of this subject.
Official Website https://d3js.org/
D3 API Reference https://github.com/d3/d3/blob/master/API.md
D3 Wiki https://github.com/d3/d3/wiki
Many pages on Mozilla Developer Network
DevDocs http://devdocs.io/d3~3/
D3 and SVG courses on http://www.teamtreehouse.com/
Wikipedia https://en.wikipedia.org/wiki/D3.js
This guide was written as an assignment for Oregon State's CS 290 course. I selected this topic because I am a business intelligence developer working with SAP's platforms including BOBJ (BusinessObjects). My team is fairly new within the company and we are quickly learning our limitations for graphical representations. I plan to leverage what I learned from researching and writing this in development of extensions for use with Design Studio. For those who are unfamiliar, Design Studio makes heavy use of CSS and JavaScript.