Table 1. The top 10 most central authors in the co-authorship networks (Scopus data).

Sample 1		Sample 2		Sample 3
Author	Betweenness	Author	Betweenness	Author	Betweenness
Bosch, F.	6885	Bosch, F.	2842	Schunn, C.D.	185
Cobo, E.	6388	Cobo, E.	2590	Cho, K.	157
Altman, D.G.	5751	Flanagin, A.	2319	Gehringer, E.F.	126
Flanagin, A.	5326	Altman, D.G.	1870	Lee, R.	108
Rennie, D.	3021	Godlee, F.	1335	Allen, L.	102
Marusic, A.	2956	Rennie, D.	892	Jones, L.S.	90
Moher, D.	1883	Cook, J.	792	Terveen, L.	72
Justice, A.D.	1705	Marusic, A.	750	Bollen, J.	62
Godlee, F.	1414	Johnson, N.	693	Van Leeuwen, T.N.	59
Cook, J.	1264	Boutron, I.	606	Trevisan, M.	56