Walker, G. (1987). Astronomical observations: An optical perspective. Cambridge University Press.
Lua i Stíl Chicago (17ú heag.)Walker, G. Astronomical Observations: An Optical Perspective. Cambridge: Cambridge University Press, 1987.
Lua MLA (9ú heag.)Walker, G. Astronomical Observations: An Optical Perspective. Cambridge University Press, 1987.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.