@article{WHO International Collaborating Group for the study of the WHO Staging System1993,
author = {WHO International Collaborating Group for the study of the WHO Staging System},
title= {Proposed 'World Health Organization staging system for HIV infection and disease': preliminary testing by an international collaborative cross-sectional study},
year = {1993},
journal = {AIDS},
volume = {7},
number = {5},
pages = {711--718},
}