by Northrop, T.G.
Published in Icarus (New York, N.Y. 1962) (01.08.1997)

by Northrop, T.G., Lisse, C.M., Mumma, M.J., Desch, M.D.
Published in Icarus (New York, N.Y. 1962) (01.05.1997)

by Northrop, Theodore G
Published in Annals of physics (01.07.1961)

by Northrop, T.G., Birmingham, T.J.
Published in Solar physics (01.09.1970)