The section in health psychology does not seem to me like a good model, with a huge list of schools and so on. The relevant bits might be the history (as presented in secondary sources) of what the requirements are to be an OHP, and who does the licensing. (To my limited understanding there are no such formal requirements in this specific field, and no formal licensing, nor would these be required in order to establish OHP as a separate academic discipline.) Just in case anyone was thinking of a long disquisition mostly from primary sources designed to show that most OHP training is done as part of i/o courses, it would save a lot of time to abandon the idea now.