Παραπομπή APA

Heel, A. C. S. v., & Velzel, C. H. F. (1968). What is light? Weidenfeld & Nicolson.

Παραπομπή Chicago Style

Heel, A. C. S. van, και C. H. F. Velzel. What Is Light? London: Weidenfeld & Nicolson, 1968.

Παραπομπή MLA

Heel, A. C. S. van, και C. H. F. Velzel. What Is Light? Weidenfeld & Nicolson, 1968.