Cita APA (7th ed.)
Hartle, J. B. Gravity: An Introduction to Einstein's General Relativity. Addison-Wesley.
Cita Chicago (17th ed.)
Hartle, James B. Gravity: An Introduction to Einstein's General Relativity. San Francisco, EUA: Addison-Wesley.
Cita MLA (9th ed.)
Hartle, James B. Gravity: An Introduction to Einstein's General Relativity. Addison-Wesley.
Atenció: Aquestes cites poden no estar 100% correctes.