Class "Gef", directly.
Class "G0", by class "Gef", distance 2.
Class "Meteo", by class "Gef", distance 3.
Class "Sol", by class "Gef", distance 3.
References
Abella, M. A., Lorenzo, E. y Chenlo, F.: PV water pumping systems based on standard frequency converters. Progress in Photovoltaics: Research and Applications, 11(3):179–191, 2003, ISSN 1099-159X.
Perpiñán, O, Energía Solar Fotovoltaica, 2012.
(http://procomun.wordpress.com/documentos/libroesf/)
Perpiñán, O. (2012), "solaR: Solar Radiation and Photovoltaic
Systems with R", Journal of Statistical Software, 50(9), 1-32,http://www.jstatsoft.org/v50/i09/