张怡筠. (2007). 工作其实很简单: Manage your work easily. 河北教育出版社.
Chicago (17e ed.) Bronvermelding张怡筠. 工作其实很简单: Manage Your Work Easily. 河北教育出版社, 2007.
MLA (8e ed.) Bronvermelding张怡筠. 工作其实很简单: Manage Your Work Easily. 河北教育出版社, 2007.
Let op: Deze citaties zijn niet altijd 100% accuraat.