LC/MS/NMR analysis of isomeric divanilloylquinic acids from the root bark of Fagara zanthoxyloides Lam. Badioré Ouattara, Luc Angenot, Pierre Guissou, Pierre Fondu, Jacques Dubois, Michel Frédérich, Olivia Jansen, Jean-Claude van Heugen, Jean-Noël Wauters and Monique Tits, Phytochemistry, Volume 65, Issue 8, April 2004, Pages 1145-1151, doi10.1016/j.phytochem.2004.02.025