Edwards PET, Parsons GR, Myers KH. The economic value of viewing migratory shorebirds on the Delaware Bay: an application of the single-site travel cost model using on-site data. Hum Dimens Wildl. 2011;16(6):435-44. doi: 10.1080/10871209.2011.608180
Lillienberg L, Zock JP, Kromhout H, Plana E, Jarvis D, Toren K. A population-based study on welding exposures at work and respiratory symptoms. Ann Occup Hyg. 2008 Mar;52(2):107-15.
Spector D, Anthony M, Alexander D, Arab L. Soy consumption and colorectal cancer. Nutr Cancer. 2003;47(1):1-12.