Custer, Thomas W.; Pitelka, Frank A. (1978). "Seasonal trends in summer diet of the Lapland longspur near Barrow, Alaska". The Condor. 80 (3): 295–301. doi:10.2307/1368039. JSTOR1368039.
Custer, Thomas W.; Pitelka, Frank A. (1978). "Seasonal trends in summer diet of the Lapland longspur near Barrow, Alaska". The Condor. 80 (3): 295–301. doi:10.2307/1368039. JSTOR1368039.