3He Q. Component Study of Co - word Analysis [ D ]. Champaign, IL, USA : University of Illinois at Urbana - Champaign,2001.
4U. S. National Library of Medicine. Indexing Manual of the National Library of Medicine [ EB/OL]. [2010 - 11 - 10]. https: //dcms. nlm. nih. gov/dcms/help/manual, cfm.
5U. S. National Library of Medicine. MEDLINE Indexing Online Training Course [ EB/OL]. [ 2010 - 11 - 10 ]. http:// www. nlm. nih. gov/bsd/indexing/training/USE_010.htm.