Wallace, L Sunspot umbral spectra in the region 4000 to 8640 cm-1 (1.16 to 2.50 m) L. Wallace, K. Hinkle and W. C. Livingston - Arizona National Solar Observatory 2001 - [various pagings.] Subjects--Topical Terms: AtlasSunspotUmbral spectra Universal Decimal Class. No.: 084.4:523.982.2 / WAL