1. The INDEPTH Network, PO Box KD 213, Accra, Ghana,
2. Mailman School of Public Health, Columbia University, New York, USA
3. Navrongo Health Research Centre, PO Box 114, Navrongo, Ghana
4. Population Council, One Dag Hammerskjold Plaza, NY 10017, New York
5. Department of Computer Science, University of Southern Maine, Portland, USA
6. School of Public Health, University of Ghana, Legon, Accra, Ghana