Simultaneous quantification of fexofenadine and pseudoephedrine in human plasma by liquid chromatography/tandem mass spectrometry with electrospray ionization: method development, validation and application to a clinical study - Nirogi, RV; Kandikere, VN; Shukla, M; Mudigonda, K; Maurya, S; Komarneni, P. (Rapid Commun Mass Spectrom., 2006)