- public library of science (plos)7
- elsevier6
- royal college of general practitioners6
- american medical association5
- caaul, lisbon, portugal.5
- cab, madrid, spain.5
- cab, madrid, spain.;inta, aguilas, spain.5
- caltech, pasadena, ca 91125 usa.5
- cardiff univ, cardiff cf10 3ax, s glam, wales.5