Bernaldo-De-Quirós, M., F. J. Labrador, G. García-Fernández, I. Fernández-Arias, F. Estupiñá, and M. Labrador-Méndez. “Factors Associated With Prolonging Psychological Treatment for Anxiety Disorders”. Psicothema, vol. 27, no. Número 2, Dec. 2015, pp. 108-13, https://reunido.uniovi.es/index.php/PST/article/view/10762.