Cita APA (7a ed.)

Green, R. F., Lisboa, J., & Yasin, M. M. (1993). Porter's (1980) generic strategies in Portugal. [s.n.].

Cita Chicago Style (17a ed.)

Green, Ronald F., Joa Lisboa, y Mahmoud M. Yasin. Porter's (1980) Generic Strategies in Portugal. [S.l.]: [s.n.], 1993.

Cita MLA (9a ed.)

Green, Ronald F., et al. Porter's (1980) Generic Strategies in Portugal. [s.n.], 1993.