Authors: J B Seward; B K Khandheria; J K Oh; M D Abel; R W Hughes; W D Edwards; B A Nichols; W K Freeman; A J Tajik Journal: Mayo Clin Proc Date: 1988-07 Impact factor: 7.616
Authors: W G Daniel; R Erbel; W Kasper; C A Visser; R Engberding; G R Sutherland; E Grube; P Hanrath; B Maisch; K Dennig Journal: Circulation Date: 1991-03 Impact factor: 29.690