Here are a few scholarly articles on PMR. There are quite a few. Google Scholar is helpful when searching for the latest medical info - https://scholar.google.com/.

-- An update on polymyalgia rheumatica:
https://onlinelibrary.wiley.com/doi/full/10.1111/joim.13525
-- Patients' views on the causes of their polymyalgia rheumatica: a content analysis of data from the PMR Cohort Study: https://bmjopen.bmj.com/content/7/1/e014301