Creating a Metamodel Based on Machine Learning to Identify the Sentiment of Vaccine and Disease-Related Messages in Twitter: the MAVIS Study. - Alejandro Rodríguez González; Juan Manuel Tuñas; Diego Fernandez Peces-Barba; Ernestina Menasalvas Ruiz; Almudena Jaramillo; Manuel Cotarelo; Antonio Conejo; Amalia Arce; Angel Gil (CBMS, 2020)