Sources

1. Castagneri, D., Garbarino, M., & Nola, P. (January 01, 2013). Host preference 
     and growth patterns of ivy (Hedera helix L.) in a temperate alluvial forest.  
     Plant Ecology, 214, 1, 1-9. 
2. English Ivy, Hedera helix - Pest Tracker - NAPIS . (n.d.). National Agricultural 
     Pest Information System. Retrieved March 6, 2013, from 
     http://pest.ceris.purdue.edu/pest.php?code=PALACBA 
3. English Ivy. (n.d.). Eastern Forest Threat Center. Retrieved March 6, 2013, 
     from http://threatsummary.forestthreats.org/threats
     /threatSummaryViewer2.cfm?threatID=98 
4. Ingham, C. S., & Borman, M. M. (April 01, 2010). English Ivy ( Hedera spp., 
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     Management, 3, 2, 178-181. 
5. Lovejoy, A. (2005, February 17). There'll be no cease-fire in this war on English 
     ivy. Seattle Post-Intelligencer, p. 1. Retrieved March 6, 2013, from 
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6. PLANTS Profile for Hedera helix (English ivy) | USDA PLANTS. (n.d.). USDA 
     PLANTS Database. Retrieved March 6, 2013, from http://plants.usda.gov
     /java/profile?symbol=HEHE 
7. Query By Name English Ivy. (n.d.). INVADERS Database System. Retrieved 
     March 6, 2013, from http://invader.dbs.umt.edu 
8. Ringold, P. L., Magee, T. K., & Peck, D. V. (December 01, 2008). Twelve 
     invasive plant taxa in US western riparian ecosystems. Journal of the North 
     American Benthological Society, 27, 4, 949-966.
9. Waggy, Melissa A. 2010. Hedera helix. In: Fire Effects Information System, 
     [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain 
     Research Station, Fire Sciences Laboratory (Producer). Available: 
     http://www.fs.fed.us/database/feis/ [2013, March 6]. 
10. Weed Detail Page English Ivy. (n.d.). Noxious Weed Control Board WA State. 
     Retrieved March 6, 2013, from http://www.nwcb.wa.gov
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11. Why are invasive species a problem?. (n.d.). BLM - The Bureau of Land 
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Sources for pictures are in the alt text.