Losey, J.E., L.S. Rayor, and M.E. Carter.
Transgenic pollen harms monarch larvae.
Pests find new ways around natural toxins. Perkins, S. 1997. Transgenic plants provoke petition . The Journey North Web site is dedicated to following the journeys of a dozen migratory species through observations by student groups throughout the Northern Hemisphere. This site is particularly notable for providing information on the weekly northern movement of monarch butterflies.