Conflicts of interest in research on electronic cigarettes. - Martínez, Cristina; Fu, Marcela; Galán, Iñaki; Pérez-Rios, Mónica; Martínez-Sánchez, Jose M.; López, Maria J.; Sureda, Xisca; Montes, Agustín; Fernández, Esteve (Tobacco Induced Diseases, 2018)