APA

Popkorn S., . (1994). First steps in modal logic. Cambridge [u.a.]: Cambridge Univ. Press.

Chicago

Popkorn Sally, . 1994. First steps in modal logic. Cambridge [u.a.]: Cambridge Univ. Press.

Harvard

Popkorn S., . (1994). First steps in modal logic. Cambridge [u.a.]: Cambridge Univ. Press.

MLA

Popkorn Sally, . First steps in modal logic. Cambridge [u.a.]: Cambridge Univ. Press. 1994.