Birbara, C., Ruoff, G., Sheldon, E., Valenzuela, C., Rodgers, A., Petruschke, R. A., Chang, D. J., Tershakovec, A. M. Efficacy and safety of rofecoxib 12.5 mg and celecoxib 200 mg in two similarly designed osteoarthritis studies. Current Medical Research and Opinion 2006; 1: 199รข?210