If you include the author's last name in your sentence, write the date in brackets
It has been argued by Harris (2001) that the main considerations are...
Alternatively, write both the author's last name and the date of publication in brackets:
It has been argued (Harris 2001) that the main considerations are...
If you paraphrase a particular argument or point from a source you should also include the
It has been argued (Harris 2001, pp. 20-21) that the main considerations
are the scope of the project, the cost and the duration of the work.
Where there is no personal author, cite the organisation which produced the publication:
Health literacy is important because people have to make critical choices about their health everyday (Centers of Disease Control and Prevention 2011).
If neither an author or an organisation is stated, cite the title of the document instead:
Google has recently launched One Pass which will enable customers to use content they've purchased on any device (Google's One Pass Could Provide Ways Around Apple Rules 2011).