UV spectrophotometric determination of bioflavonoids from a semisolid pharmaceutical dosage form containing Trichilia catigua Adr. Juss and Ptychopetalum olacoides Bentham standardized extract: analytical method validation and statistical procedures - Baby, André Rolim; Maciel, Carolina Penteado Moraes; Kaneko, Telma Mary; Velasco, Maria Valéria Robles (Journal of AOAC International, 2006)