Nave, Carl Rod. "The Thin Lens Equation". HyperPhysics (بالإنجليزية). Georgia State University. Archived from the original on 2018-01-21. Retrieved 2017-08-08.
mit.edu
ocw.mit.edu
Barbastathis, George; Sheppard, Colin. "Real and Virtual Images"(PDF). MIT OpenCourseWare (بالإنجليزية). Massachusetts Institute of Technology. p. 4. Archived from the original(Adobe Portable Document Format) on 2017-08-30. Retrieved 2017-08-08.
Barbastathis, George; Sheppard, Colin. "Real and Virtual Images"(PDF). MIT OpenCourseWare (بالإنجليزية). Massachusetts Institute of Technology. p. 4. Archived from the original(Adobe Portable Document Format) on 2017-08-30. Retrieved 2017-08-08.
Nave, Carl Rod. "The Thin Lens Equation". HyperPhysics (بالإنجليزية). Georgia State University. Archived from the original on 2018-01-21. Retrieved 2017-08-08.