APA (7th ed.) Citation

Engels, F., Lafargue, P., & Lafargue, L. (1956). Correspondance. Éditions Sociales.

Chicago Style (17th ed.) Citation

Engels, Friedrich, Paul Lafargue, and Laura Lafargue. Correspondance. París: Éditions Sociales, 1956.

MLA (9th ed.) Citation

Engels, Friedrich, et al. Correspondance. Éditions Sociales, 1956.