Gething PW, Noor AM, Goodman CA, Gikandi P, Hay SI, Sharif SK, Atkinson P, Snow RW(2007). Information for decision making from imperfect national data: tracking major changes in health care use in Kenya using geostatistics. BMC Medicine, 5: e37[PMCID: 2225405] ,[PMID: 18072976]