https://zedload.com/download/social-media-marketing-guido-di-fraia-2026-retail.html
https://eurekaddl.art/book/guido-di-fraia-social-media-marketing-2015/
https://eurekaddl.art/book/guido-di-fraia-social-media-marketing-manuale-di-comunicazione-aziendale-2-0-2011/