APA (7th ed.) Citation

Barreno, M. I., Horta, M. T., & Costa, M. V. d. (1975). New Portuguese letters. Gollancz.

Chicago Style (17th ed.) Citation

Barreno, Maria Isabel, Maria Teresa Horta, and Maria Velho da Costa. New Portuguese Letters. London: Gollancz, 1975.

MLA (8th ed.) Citation

Barreno, Maria Isabel, et al. New Portuguese Letters. Gollancz, 1975.