CONNECTIVE TISSUE GRAFT VERSUS XENOGENEIC COLLAGEN MATRIX FOR SOFT TISSUE AUGMENTATION AT IMPLANT SITES: A RANDOMIZED-CONTROLLED CLINICAL TRIAL Article Ashurko Igor, Tarasenko Svetlana, Esayan Aleksandr, Kurkov Alexandr, Mikaelyan Karen, Balyasin Maxim, Galyas Anna, Kustova Julia, Taschieri Silvio, Corbella Stefano Clinical Oral Investigations. Springer-Verlag GmbH. Vol. 26. 2022. P. 7191-7208