ITIL® whitepapers are writings on the topics related to ITIL® concept, services, research and functions. No one is specially designated to write papers; in fact you can be an author of ITIL® whitepaper and make it available to the public. ITIL® whitepapers are interesting to read because they are very enlightening (as most of the authors write through experience). It is equally possible that whatever is available may or may not be true. Therefore, do not believe the facts until they have reliable sources.
The best way to look for ITIL® white paper is through search engines. Lot of material is available on ITIL® related websites. It depends entirely on how you regulate your search. Try to develop some kind of rating system for yourself. Whatever you learn and understand has been developed on case by case basis.