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web.archive.org
Stephen D Pratt: Clinical Forum Revisited: The "P" Value. [w:] Spring 2003 newsletter [on-line]. The Society for Obstetric Anesthesia and Perinatology (SOAP). s. 9–11. [dostęp 2007-07-09]. [zarchiwizowane z tego adresu (2008-05-09)].