Gaya APA
Spencer, W, H, .. (1983).
Optics, refraction, and contact lenses (sec. 2).
California:
American Academy of Ophtalmology.
Gaya MLA
Spencer, William, H, ..
"Optics, refraction, and contact lenses".
sec. 2
California:
American Academy of Ophtalmology,
1983.
Buku.