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2. https://www.epigenesys.org.uk/portfolio/sampsize//
3. CHMP Guideline on the choice of non-inferiority margin http://www.ema.europa.eu/docs/en_GB/document_library/Scientific_guideline/2009/09/WC500003636.pdf
4. FDA Guidance for Industry Non-inferiority clinical trials (draft) 2010
5. Tutorial in Biostatistics: Sample sizes for clinical trials with Normal Data;Julious;Statistics in Medicine,2004