Hello! Thanks for submitting your question.
You can find the following example, which I’ve cut and pasted, under the Use Policy for the Community Tool Box (http://ctb.ku.edu/en/use-policy).
HOW TO CREDIT MATERIAL FROM THE COMMUNITY TOOL BOX
In order to cite the Community Tool Box, we suggest that you use the citation format of the American Psychological Association. Detailed information about their citation format is available in a tutorial at their website. An example citation for a section from the tools appears below.
Center for Community Health and Development. (2017). Chapter 3, Section 10: Conducting Concerns Surveys. Lawrence, KS: University of Kansas. Retrieved January 2, 2017, from the Community Tool Box: http://ctb.ku.edu/en/table-of-contents/assessment/assessing-community-needs-and-resources/conduct-concerns-surveys/main.
Best wishes in your endeavors!