World Ionosphere/Thermosphere Study ; edited by C.H. Liu ; published for the ICSU Scientific Committee on Solar-Terrestrial Physics (SCOSTEP) with financial assistance from Unesco subvention through a 1989 grant from ICSU
edited by James W. Gillett, and James M. Witt, technical editor: C.J. Wyatt ; prepared for the National Science Foundation, Directorate for Applied Science and Research Applications, Division of Problem-Focused Research Applications