Cita APA (7a ed.)

Villanova, S., Baume, G., Carraro, G., & Geminale, A. (2004). Optical photometry and spectral classification in the field of the open cluster NGC 6996 in the North America Nebula.

Cita Chicago Style (17a ed.)

Villanova, S., Gustavo Baume, G. Carraro, y A. Geminale. Optical Photometry and Spectral Classification in the Field of the Open Cluster NGC 6996 in the North America Nebula. 2004.

Cita MLA (8a ed.)

Villanova, S., et al. Optical Photometry and Spectral Classification in the Field of the Open Cluster NGC 6996 in the North America Nebula. 2004.