1. Allan, R.R.; ‘Satellite Orbit Perturbations Due to Radiation Pressure and Luni-Solar Forces’, Technical Note No. Space 7, Royal Aircraft Establishment, Farnborough, England (1962).
2. Allan, R.R.; ‘Perturbation of a Geostationary Satellite — 2. Lunisolar Effects’, Technical Note No. Space 47, Royal Aircraft Establishment, Farnborough, England (1963).
3. Allan, R.R. and Cook, G.E.; ‘The Long-Period Motion of the Plane of a Distant Circular Orbit’, Proceedings of Royal Society (London) A280, 97–109 (1964).
4. Bogoliubov, H. and Mitropolsky, J.; Asymptotic Method in the Theory of Nonlinear Oscillations, Hindustan Publishing Corporation, Delhi-6, India, 1961.
5. Brouwer, D. and Clemence, G.M.; Methods of Celestial Mechanics, Academic Press, New York and London, 1961.