“…In approximately half of the studies, questionnaires were administered face-to-face (n = 21/43) [2,21,26,30,34,35,[38][39][40][41][42][43][44][45][46][47][48]56,58,61], however, two of them combined the faceto-face interview with the on-line administration [44,61]. Seven studies used on-line administration [24,[27][28][29]33,54,60], five studies performed a self-administration (paperbased) [22,32,37,49,51] and two studies used a telephone administration [36,50]. Eight studies did not report information regarding administration methods [20,23,25,31,52,53,55,59].…”