Fliegel, H.F. and Hawkins, T.P., "Analysis of Variations in the Rotation of the Earth," (3 Copies), from The Astronomical Journal, Vol. 72, No. 4, No. 1349, May,, 1967

Fliegel, H.F. and Hawkins, T.P., "Analysis of Variations in the Rotation of the Earth," (3 Copies), from The Astronomical Journal, Vol. 72, No. 4, No. 1349, May,, 1967. Georgetown Observatory Collection, GRB-000010. Georgetown University Rare Books , Booth Family Center for Special Collections. https://findingaids.library.georgetown.edu/repositories/14/archival_objects/1163435 Accessed December 24, 2025.