How do I cite a source that has no date?
Answer
Replace the date element with the initials (n.d.).
Note: Do not use the copyright year on websites. Copyright on webpages refers to legal ownership and not the publication date.
Create a reference
Template 
Organizational Name or Author(s) last name, initial. (n.d.). Title. Source.
Example
Centers for Disease Control and Prevention. (n.d.). Influenza prevention: Information for travellers. https://www.cdc.gov/flu/school-business/travelersfacts.htm
Create a citation
Template
(Organizational Author Name, Year of publication )
(Organizational Author Name, Year of publication, p. #)
Example
(Centers for Disease Control and Prevention, n.d.) 
(Centers for Disease Control and Prevention, n.d, p. 8)
For more information and examples, see the APA's blog post on how to incorporate missing information into citations and references.
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