RT Journal Article SR Electronic T1 Vitamin D deficiency, a potential cause for insufficient response to sildenafil in pulmonary arterial hypertension JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 2101204 DO 10.1183/13993003.01204-2021 VO 58 IS 5 A1 María Callejo A1 Isabel Blanco A1 Joan Albert Barberá A1 Francisco Perez-Vizcaino YR 2021 UL http://erj.ersjournals.com/content/58/5/2101204.abstract AB