Answered By: Michael Pujals Last Updated: Nov 30, 2015 Views: 52
I'm going to assume you're using APA. It would be best to find the original paper by Lambert and Barley and then you could cite it directly, otherwise you would cite this as a secondary source (section 6.17, page 178 in the APA Manual)
it would look something like this;
Lambert and Barley state: "My profession presents and makes up the slides on therapeutic alliance" (as cited in Harris, 2015). And then in our references cite Patricia Harris.