APA

Leffler S. J., . (1989). The Design and implementation of the 4.3BSD Unix operating system. Reading, Mass: Addison-Wesley Publ. Comp.

Chicago

Leffler Samuel J, . 1989. The Design and implementation of the 4.3BSD Unix operating system. Reading, Mass: Addison-Wesley Publ. Comp.

Harvard

Leffler S. J., . (1989). The Design and implementation of the 4.3BSD Unix operating system. Reading, Mass: Addison-Wesley Publ. Comp.

MLA

Leffler Samuel J, . The Design and implementation of the 4.3BSD Unix operating system. Reading, Mass: Addison-Wesley Publ. Comp. 1989.