It is common for an author to cite another in their own publication. If you have not read the original text then you must apply the following:

A direct in-text reference:

Research recently carried out in Kent by Phillips (1992 cited in Jones, 1999, p.111) finds … In the above example, Phillips is the work which you want to reference, but have not read directly for yourself. Jones is the secondary source, where you found the summary of Phillip’s work. An indirect in-text citation would be: (Phillips, 1992 cited in Jones, 1999, p.111) It is important to recognise that Jones may have taken Phillip’s ideas, and altered their original meaning. Therefore, if you choose to cite a secondary reference it is recommended that, where possible, you read the original source for yourself rather than rely on someone else’s interpretation of a work.