Outcomes of sleeve gastrectomy in patients older than 60 years: a multicenter matched case-control study - Natalia Dowgiałło-Wnukiewicz; Michal R. Janik; Pawel Lech; Piotr Major; Michał Pędziwiatr; Piotr K. Kowalewski; Maciej Walędziak; Michał Wysocki; Maciej Michalik (Videosurgery and Other Miniinvasive Techniques)