约翰 & 史密斯. (2018). 企鹅有烦恼: Penguin problems. 北京联合出版公司.
Chicago Style (17th ed.) Citation约翰 and 史密斯. 企鹅有烦恼: Penguin Problems. 北京联合出版公司, 2018.
MLA (8th ed.) Citation约翰 and 史密斯. 企鹅有烦恼: Penguin Problems. 北京联合出版公司, 2018.
Warning: These citations may not always be 100% accurate.