Columbia subject headings:
Drama--20th century--History and criticism.
Dramatists--Bio-bibliography.
Theater--Dictionaries.
Harvard subject headings:
Drama--20th century--History and criticism
Dramatists--Bio-bibliography.
Theater--Dictionaries.
Princeton subject headings:
Dictionaries.
Drama--20th century--History and criticism.
Drama--Bio-bibliography--Dictionaries.
Theater--Dictionaries.