Structure determination of hydroxytrypargine: A new tetrahydro-'beta'carboline toxin from the venom of the spider Parawixia bistriata - Cesar, Lilian Mari Marcondes; Tormena, Cláudio F.; Marques, Maurício R.; Silva, Gil Valdo José da; Mendes, Maria A.; Rittner, Roberto; Palma, Mário S. (Helvetica Chimica Acta, 2005)