Columbia subject headings:
Cancer--Chemotherapy--Congresses.
Folic acid--Antagonists--Therapeutic use--Testing--Congresses.
Folic acid--Derivatives--Therapeutic use--Testing--Congresses.
Harvard subject headings:
Cancer--Chemotherapy--Congresses
Folic acid--Antagonists--Therapeutic use--Testing--Congresses.
Folic acid--Derivatives--Therapeutic use--Testing--Congresses.
Princeton subject headings:
Folic acid--Congresses.
Tumors--Chemotherapy--Congresses.