Ground Level enhancements of solar cosmic rays (1956-2006): Study of Solar and
Interplanetary Aspects

L.I. Miroshnichenko, E.V. Vashenyuk, Yu.V. Balabin, J.Pérez-Peraza, B.B. Gvozdevsky
Proc. de la 31ava Conf. Int. de Rayos Cósmicos, SH.1.5-8 ,CD-ROM, 2009.