INS and type 2 diabetes mellitus: 23 Holman Holman RR RR Thorne Thorne KI KI Farmer Farmer AJ AJ Davies Davies MJ MJ Keenan Keenan JF JF Paulo Paulo S S Levy Levy JC JC 4-T Study Group 4-T Study Group Addition of biphasic, prandial, or basal insulin to oral therapy in type 2 diabetes Addition of biphasic, prandial, or basal insulin to oral therapy in type 2 diabetes N Engl J Med N Engl J Med 2007 2007 357 357 17 17 1716 1716 1730 1730 17890232 17890232