Liraglutide versus sitagliptin for patients with type 2 diabetes who did not have adequate glycaemic control with metformin: a 26-week, randomised, parallel-group, open-label trial. - Pratley, Richard E.; Nauck, Michael; Bailey, Timothy; Montanya, Eduard; Cuddihy, Robert; Filetti, Sebastiano; Thomsen, Anne Bloch; Sønderqaard, Rie Elvang; Davies, Melanie (Lancet, 2010)