Source: https://www.researchgate.net/profile/Marcello_Maggio/publication/346386762_Citation_Comprehensive_Model_for_Physical_and_Cognitive_Frailty_Current_Organization_and_Unmet_Needs/links/5fbf64f0a6fdcc6cc669ca0c/Citation-Comprehensive-Model-for-Physical-and-Cognitive-Frailty-Current-Organization-and-Unmet-Needs.pdf