@book{13431,
	author = {Wallace, L. and Hinkle, K.},
	title = {An atlas of sunspot umbral spectra in the visible from 15000 to 25500cm-1 (3920 to 6664 A)},
	publisher = {National Solar Observatory},
	year = {2000},
	series = {NSO technical report; no. 1},
	address = {Tucson}
}