APA Citation

Petkov, P. M. (1991). The United States and Bulgaria in World War I. Boulder CO:: East European Monographs.

Chicago Style Citation

Petkov, Petko M. The United States and Bulgaria in World War I. Boulder CO:: East European Monographs, 1991.

MLA Citation

Petkov, Petko M. The United States and Bulgaria in World War I. Boulder CO:: East European Monographs, 1991.

Warning: These citations may not always be 100% accurate.