High-performance liquid chromatography with on-line coupled UV, mass spectrometric and biochemical detection for identification of acetylcholinesterase inhibitors from natural products - Ingkaninan, K; de Best, C M; van der Heijden, R; Hofte, A JP; Karabatak, B; Irth, H; Tjaden, U R; van der Greef, J; Verpoorte, R (J Chromatog A, 2000)