Παραπομπή APA

Coles, P., & Ellis, G. F. R. (1997). Is the universe open or closed? Cambridge University Press.

Παραπομπή Chicago Style

Coles, Peter, και George Francis Rayner Ellis. Is the Universe Open or Closed? Cambridge: Cambridge University Press, 1997.

Παραπομπή MLA

Coles, Peter, και George Francis Rayner Ellis. Is the Universe Open or Closed? Cambridge University Press, 1997.