Below are some apps I have identified that may be useful for research. Not all of these will be applicable to the way you work but they are a place to start. Also, don't forget Evernote as a research tool. It could easily have gone in here instead of Document Sharing/Productivity.
A mind map is a diagram used to visually outline information. A mind map is often created around a single word or text, placed in the center, to which associated ideas, words and concepts are added. As with other diagramming tools, mind maps can be used to generate, visualize, structure, and classify ideas, and as an aid to studying, and organizing information, solving problems, making decisions, and writing.