Cita APA (7a ed.)

Gutiérrez Moreno, A., Moreno, H., & Cortés, G. (1990). Two planetary nebulae near the galactic center.

Cita Chicago Style (17a ed.)

Gutiérrez Moreno, A., H. Moreno, y G. Cortés. Two Planetary Nebulae Near the Galactic Center. 1990.

Cita MLA (8a ed.)

Gutiérrez Moreno, A., et al. Two Planetary Nebulae Near the Galactic Center. 1990.