Columbia subject headings:
Cancer--Radiotherapy--Congresses.
Hematoporphyrin--Therapeutic use--Congresses.
Laser coagulation--Congresses.
Photochemotherapy--Congresses.
Porphyrins--Therapeutic use--Congresses.
Harvard subject headings:
Cancer--Photochemotherapy--Congresses
Hematoporphyrin--Therapeutic use--Congresses.
Laser coagulation--Congresses.
Porphyrins--Therapeutic use--Congresses.
Princeton subject headings: