title: Analysis of Pyrrolizidine Alkaloids from the Symphytum officinale Species Complex and S. asperum.
authors.affiliation: Laboratory for Pharmacognosy and Galenic Pharmacy, Ant. Deusinglaan 2, 9713 AW Groningen, The Netherlands.
authors.forename: H J
authors.initials: HJ
authors.lastname: Huizing