J. A.  Zavala, Giri, A. P., Jongsma, M. A., and Baldwin, I. T., ?Digestive duet: midgut digestive proteinases of manduca sexta ingesting nicotiana attenuata with manipulated trypsin proteinase inhibitor expression?, Plos One, vol. 3, no. 4, p. e2008, 2008.