I am pleased to draw your attention to pubMed (http://www.ncbi.nlm.nih.gov/pubmed/), There you will actually find 4617 papers filed up, many of them sadly without abstract but many of them will give you interesting clues, for example to evaluate the links between independence and organizational mission, to assess market factors, to analyze the organization's financial status, to perform a strategic assessment, to evaluate the potential benefits of partnership, to assess the organization's ability to implement strategy etc. Using the filtering system you may encircle interesting subjects and by doing so you will have a valuable thesaurus easily and quite comfortably this evening. Tomorrow you may order the literature and next week you can begin to follow and sort the literature listed in the papers. I am sure, this thesaurus will cover most subjects interesting and relevant for your research.
Sorry, I forgot: As a second idea I would search with the key word "Management of Hospital Mergers" in Google Scholar. Your will find there a bonanza as well.