Brigner W L, Deni J R
Appalachian State University.
Percept Mot Skills. 1994 Feb;78(1):17-8. doi: 10.2466/pms.1994.78.1.17.
Using the single staircase psychophysical method, the apparent depth threshold for the Benussi effect was determined for 5 observers. The threshold occurred at an eccentricity of 2r/3, where r equals the radius of the larger circle expressed in millimeters.