1. Arfken, G. (1985). Spherical Polar Coordinates. Mathematical Methods for Physicists, 3 edition.
2. Bao, G., Zhou, Z., Xiong, S., Lin, X., and Ye, X. (2003). Towards micro air vehicle flight autonomy research on the method of horizon extraction. In Instrumentation and Measurement Technology Conference. IMTC'03. Proceedings of the 20th IEEE. IEEE
3. Canny, J. (1987). A computational approach to edge detection. Readings in computer vision: issues, problems, principles, and paradigms, IEEE Trans. Pattern
4. Cornall, T. and Egan, G. (2005). Calculating attitude from horizon vision. In Eleventh Australian International Aerospace Congress, Melbourne
5. Demonceaux, C., Vasseur, P., and Pegard, C. (2006). Robust attitude estimation with catadioptric vision. In International Conference on Intelligent Robots and Systems 2006 IEEE/RSJ, 3448–3453. IEEE/RSJ.