1. Toxic pyrrolizidine alkaloids in comfrey;Mattocks;Lancet,1980
2. The pyrrolizidine alkaloids;Bull,1968
3. Determination of pyrrolizidine alkaloid content and composition in Senecio species by NMR spectroscopy;Molyneux;J Agric Food Chem,1979
4. The alkaloids of Symphytum x uplandicum (Russian comfrey);Culvenor;Aust J Chem,1980
5. The toxic actions of pyrrolizidine (Senecio) alkaloids;McLean;Pharmacol Rev,1970