TY - JOUR A1 - Echer, E. A1 - Rigozo, N. R. A1 - Nordemann, D. J. R. A1 - Vieira, L. E. A. T1 - Prediction of solar activity on the basis of spectral characteristics of sunspot number JO - Ann. Geophys. J1 - ANGEO VL - 22 IS - 6 SP - 2239 EP - 2243 Y1 - 2004/06/14 PB - Copernicus Publications SN - 1432-0576 UR - https://angeo.copernicus.org/articles/22/2239/2004/ L1 - https://angeo.copernicus.org/articles/22/2239/2004/angeo-22-2239-2004.pdf DO - 10.5194/angeo-22-2239-2004 ER -