Correction: Characterization of Anorexia Nervosa on Social Media: Textual, Visual, Relational, Behavioral, and Demographical Analysis - Diana Ramírez-Cifuentes; Ana Freire; Ricardo Baeza-Yates; Nadia Sanz Lamora; Aida Álvarez; Alexandre González-Rodríguez; Meritxell Lozano Rochel; Roger Llobet Vives; Diego Alejandro Velazquez; Josep Maria Gonfaus; Jordi Gonzàlez (JMIR Publications, 2021)