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
Miron A, Schildkraut JM, Rimer BK, Winer EP, Sugg Skinner C, Futreal PA, Culler D, Calingaert B, Clark S, Kelly Marcom P, Iglehart JD. Testing for hereditary breast and ovarian cancer in the Southeastern United States. Ann Surg. 2000 May;231(5):624-34.