It can probably be concluded that nearly every tool can be considered a reference work. Especially with electronic resources that can be searched in the fulltext or by using the index and table of contents to lead one to specific references. The list is endless but asking for assistance can direct you to the appropriate dictionary, handbook, glossary, encyclopedia, case study, map, data element, map, piece of legislation, etc.
There are many sources that describe the work environment that of Allied and Public Health and salary scales that currently show national averages.