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
Rothman KJ, Wepsic JG. Side of facial pain in trigeminal neuralgia. J Neurosurg. 1974 Jan 1;40(4):514-6.