1. Papirno, R., andBecker, H., “A Multilayer-reflection Technique for Three-dimensional Photoelastia Studies of Perforated Plates in Bending,”Experimental Mechanics,7, (9),361–371 (1967).
2. Aben, H. K., “On the Investigation of Three-dimensional Photo-elastic Models” (in Russian),Izv. Akad. Nauk SSSR, Mekh. i Mashinostr.,4,40–46 (1964).
3. Aben, H. K., “Optical Phenomena in Photoelastic Models by the Rotation of Principal Axes,”Experimental Mechanics,6, (1),137–146 (1966).
4. Poincaré, H., “Theorie Mathématique de la Lumière, II,” Paris (1892).
5. Aben, H., “On the Experimental Determination of Parameters of Complex Optical Systems” (in Russian),Izv. Akad. Nauk Estonian SSR, ser. Fiz.-Mat. i Tekh. Nauk,13, (4),329–343 (1964).