How experts on Autoinflammatory diseases classify Periodic Fever, Aphthous stomatitis, Pharyngitis and Cervical Adenitis (PFAPA): preliminary results of the Eurofever Delphi survey. Issue 1 (December 2015) - Vanoni, F; Federici, S; Ozen, S; Frenkel, J; Lachmann, H; Martini, A; Ruperto, N; Gattorno, M; Hofer, M