The GIPAD handbook of the gastrointestinal pathologist (in the Covid-19 era): Editorial - Parente, Paola; Battista, Serena; Unti, Elettra; D’Amuri, Alessandro; Vanoli, Alessandro; Mastracci, Luca; Fassan, Matteo (Pathologica - Journal of the Italian Society of Anatomic Pathology and Diagnostic Cytopathology, 2020)