1. A photometric investigation of the slopes and heights of the ranges and hills in the maria of the moon;Van Diggelen;Bull. Astron. Inst. Netherlands,1951
2. Photometric method for lunar topography;Rindfleisch;Photogrammetric Engineering,1966
3. Obtaining shape from shading information;Horn,1975
4. Understanding image intensities;Horn;Artificial Intelligence,1977
5. A cooperative algorithm for determining surface orientation from a single view;Woodham,1977