Effectiveness of interventions for the prevention of occupational violence against professionals in health services: a protocol for a systematic review - Okubo, Caroline Vieira Cláudio; Silveira, Renata Cristina de Campos Pereira; Galdino, Maria José Quina; Fernandes, Daiane Rubinato; Moreira, Aline Aparecida Oliveira; Martins, Júlia Trevisan (BMJ Open, 2020)