Columbia subject headings:
Medicine--History--Audio-visual aids--Directories.
Science--History--Audio-visual aids--Directories.
Technology--History--Audio-visual aids--Directories.
Harvard subject headings:
Medicine--History--Audio-visual aids--Directories.
Science--History--Audio-visual aids--Directories.
Technology--History--Audio-visual aids--Directories.
Princeton subject headings:
Medicine--History--Audio-visual aids--Directories.
Science--History--Audio-visual aids--Directories.
Technology--History--Audio-visual aids--Directories.