Population size of snowy plovers breeding in North America - Thomas, Susan; Lyons, James E.; Andres, Brad; T-Smith, Elise; Palacios, Eduardo; Cavitt, John; Royle, J. Andrew; Fellows, Suzanne; Maty, Kendra; Howe, William; Mellink, Eric; Melvin, Stefani; et al. (Waterbirds, 2012)