Jesus-Ribeiro, Joana, Elsa Vieira, Pedro Ferreira, Cristina Januário, and António Freire. 2017. “Reliability and Validity of 39-Item Parkinson’s Disease Questionnaire and Parkinson’s Disease Quality of Life Questionnaire”. Acta Médica Portuguesa 30 (5). Lisbon, Portugal:395-401. https://doi.org/10.20344/amp.8202.