Publications: I focus on a few magazines and newspapers that consistently covered Prince's career. I look through all of the relevant articles that were published during the chapter's time period.
Interviews: I go back through the transcriptions of relevant interviews that I've done.
Notes: I have a really long, scary document full of notes that I take. For example, when I'm working on a chapter, I may have a thought that I'd like to explore later in the book. So, I write it down and I make sure I review my notes periodically.
Previous Drafts: I started this project back during my undergraduate studies, so I have several old drafts of the book. I like to look back at them for things to include in this new draft.
Previous Biographies: I have a few go-to Prince biographies that I consult to help me with my book. I often use them as a base, and then add my own research because my angle is very different.
Music and Performances: I always analyze Prince's relevant lyrics, videos and concerts.
Liner Notes: I study the liner notes in the relevant album.
Award Shows: I pay attention to speeches that Prince has given at relevant award shows.
Fan Magazines: This is actually a new "source." There were several Prince fan magazines that popped up in the late 1980s and early 1990s. I intend to start reading them after I finish chapter nine.