Columbia subject headings:
Harvard subject headings:
Biological libraries--Directories.
Life sciences--Databases--Directories.
Medical libraries--Directories.
Medical sciences--Databases--Directories.
Princeton subject headings:
Biological libraries--Directories.
Biology--Bibliography--Data bases--Directories.
Biology--Information services--Directories.
Medical libraries--Directories.
Medicine--Bibliography--Data bases--Directories.
Medicine--Information services--Directories.