Martínez Pulido, A. y Francisco Garat, E. 1997. The ionospheric F2 region winter anomaly and its dependence on solar activity in the northern and southern hemispheres. Geofísica Internacional. 36, 2 (abr. 1997), 121–126. DOI:https://doi.org/10.22201/igeof.00167169p.1997.36.2.1296.