Your questions produced really interesting and informative results.
Effective research requires a strategy.
Keep a log of your research as you go along, including sources that turned out to be dead ends. This helps prevent retracing your steps, doing something twice, and having to relocate a source that you originally thought was irrelevant and now realize has helpful information. Keep citations, in Bluebook form, of each source as you go along. This will prove incredibly time-saving in the end. Thanks to all for your excellent insights and advice.