Multistage Sampling : A type of sampling in which the sample is selected by stages, the sampling units at each stage being subsampled from the larger units chosen at the previous state (ISO, 1977)
International Programme on Chemical Safety IPCS (A joint venture of the United Nations Environment Programme UNEP, the International Labour Organisation, ILO and the World Health Organization WHO), Glossary of Terms on Chemical Safety for Use in IPCS Publications, World Health Organization, Division of Environmental Health, World Health Organization, Geneva, Switzerland, ILO 1996-2010. http://www.ilo.org/legacy/english/protection/safew ork/cis/products/safetytm/glossary.ht, (IPCS Chem Sfty - Brit) {103}