Dyfyniad APA

Hawking,Stephen, & Penrose,Roger. (1999). The Nature of Space and Time. OUP.

Dyfyniad Arddull Chicago

Hawking,Stephen, and Penrose,Roger. The Nature of Space and Time. Delhi: OUP, 1999.

Dyfyniad MLA

Hawking,Stephen, and Penrose,Roger. The Nature of Space and Time. OUP, 1999.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.