Zhen, H., Lawson, A.B., McDermott, S., Pande Lamichhane, A. and Aelion, M. 2008. A spatial analysis of mental retardation of unknown cause and maternal residence during pregnancy. Geospatial Health. 2, 2 (May 2008), 173–182. DOI:https://doi.org/10.4081/gh.2008.241.