Coincidence method for focusing
Tài liệu tham khảo
G. V. Pogarev, Measurement of the Thickness, Radii of Curvature, and Focal Distances, Control of the Surface Shape of Optical Elements [in Russian], LITMO, Leningrad (1963).
V. A. Afanas'ev, Optical Measurements [in Russian], Geodezizdat, Moscow (1961).