References
- Helmholtz , H. V. 1924 . Treatise on physiological optics , Edited by: Southall , J. P. C. vols. 1 and 3 , xxi+482 xix+736 Menasha, Wis. : Optical Soc. Amer. . (See esp. v. 1, 127–128, and v. 3, 389.)
- Maier , N. R. F. 1929 . The illusion of size in pinhole vision . Amer. J. Psychol , 41 : 291 – 295 .