文本

Wolfram Research (2008)，DirectoryQ，Wolfram 语言函数，https://reference.wolfram.com/language/ref/DirectoryQ.html （更新于 2016 年）.

CMS

Wolfram 语言. 2008. "DirectoryQ." Wolfram 语言与系统参考资料中心. Wolfram Research. 最新版本 2016. https://reference.wolfram.com/language/ref/DirectoryQ.html.

APA

Wolfram 语言. (2008). DirectoryQ. Wolfram 语言与系统参考资料中心. 追溯自 https://reference.wolfram.com/language/ref/DirectoryQ.html 年

BibTeX

@misc{reference.wolfram_2025_directoryq, author="Wolfram Research", title="{DirectoryQ}", year="2016", howpublished="\url{https://reference.wolfram.com/language/ref/DirectoryQ.html}", note=[Accessed: 02-May-2026]}

BibLaTeX

@online{reference.wolfram_2025_directoryq, organization={Wolfram Research}, title={DirectoryQ}, year={2016}, url={https://reference.wolfram.com/language/ref/DirectoryQ.html}, note=[Accessed: 02-May-2026]}