1. Managing Cancer Pain: Basic Principles and Invasive Treatments
Kenneth A. Marshall, M.D. 
Mayo Clinic Proceedings 
Volume 71, Issue 5, Pages (May 1996)
DOI: /
Copyright © 1996 Mayo Foundation for Medical Education and Research Terms and Conditions

2. Fig. 1
Analgesic ladder developed by World Health Organization for management of cancer pain.
Mayo Clinic Proceedings  , DOI: ( / )
Copyright © 1996 Mayo Foundation for Medical Education and Research Terms and Conditions