Pocock SJ (1977). «Group sequential methods in the design and analysis of clinical trials». Biometrika. 64: 191–9. JSTOR2335684. doi:10.1093/biomet/64.2.191
Pocock SJ (1977). «Group sequential methods in the design and analysis of clinical trials». Biometrika. 64: 191–9. JSTOR2335684. doi:10.1093/biomet/64.2.191