Aller, L. H. (1956). Gaseous nebulae. Chapman and Hall.
Cita Chicago (17th ed.)Aller, Lawrence H. Gaseous Nebulae. 37 Essex Street, W.C.2: Chapman and Hall, 1956.
Cita MLA (9th ed.)Aller, Lawrence H. Gaseous Nebulae. Chapman and Hall, 1956.
Atenció: Aquestes cites poden no estar 100% correctes.