While Doug Cutting didn't write a single "academic" paper that defined the theory, the architecture described in the Lucene documentation relies heavily on:
Ethical research only. Do not access, download, or manipulate data without explicit permission. index of files
If you have a directory index exposed unintentionally, consider it an open door until proven otherwise. While Doug Cutting didn't write a single "academic"
intitle:"index of /" mp3 – Commonly used by data hoarders to find unshielded audio repositories. index of files