APA引文

(Firm), M., & (Firm), P. (1999). Iowa. [S.l.].

Chicago Style Citation

(Firm), Maps.com, and ProQuest (Firm). Iowa. [S.l.], 1999.

MLA引文

(Firm), Maps.com, and ProQuest (Firm). Iowa. [S.l.], 1999.

警告：這些引文格式不一定是100％准確.