Cita APA (7a ed.)

Cappa, C. E., Niemelä, V. S., Martín, M., & McClure-Griffiths, N. M. (2005). HI bubbles surrounding southern optical ring nebulae: Anon (WR 23) and RCW 52.

Cita Chicago Style (17a ed.)

Cappa, Cristina Elisabet, Virpi Sinikka Niemelä, M. Martín, y N. M. McClure-Griffiths. HI Bubbles Surrounding Southern Optical Ring Nebulae: Anon (WR 23) and RCW 52. 2005.

Cita MLA (8a ed.)

Cappa, Cristina Elisabet, et al. HI Bubbles Surrounding Southern Optical Ring Nebulae: Anon (WR 23) and RCW 52. 2005.