1. Handling missing values in the MDS-UPDRS
2. US Food and Drug Administration. FDA guidance on conduct of clinical trials of medical products during COVID‐19 public health emergency. https://www.fda.gov/regulatory‐information/search‐fda‐guidance‐documents/fda‐guidance‐conduct‐clinical‐trials‐medical‐products‐during‐covid‐19‐public‐health‐emergency. Accessed March 20 2020.
3. European Medicines Agency. Guidance on one management of clinical trials during the Covid‐19 (coronavirus) pandemic version 2.https://ec.europa.eu/health/sites/guidanceclinicaltrials_covid19. Acessed March 30 2020.