Development of a Sensitive and Specific Solid Phase Extraction− Gas Chromatography− Tandem Mass Spectrometry Method for the Determination of Elenolic Acid, Hydroxytyrosol, and Tyrosol in Rat Urine - Bazoti, Fotini N; Gikas, Evangelos; Puel, Caroline; Coxam, Véronique; Tsarbopoulos, Anthony (Journal of agricultural and food chemistry, 2005)