Harvard Style Guide: Secondary sources

It is always better to read and cite the original source of your information. If that is not possible then cite the item as a "secondary source"; a source that refers to the work of someone else. 

When referring to the work of an author whom you have read in another source, but not read directly yourself, list the full details of the secondary source in the reference listing and in your in-text citation use the term "cited in" or "citing". In the reference list format the secondary reference as you would any reference of that type. For example a journal article below is shown.

Reference: Author Last name, Initials. (Year) 'Article title', Journal Title, Volume(Issue), pp. page numbers.  

Example:

Seeberg, P. (2013) 'The Arab Uprisings and the EU's migration policies - the cases of Egypt, Libya, and Syria', Democracy and Security, 9(1-2), pp. 157-176.

In-Text-Citation:

• Secondary Author Last name (Year, page no.) cites Original Author's surname (Year)....
• (Original Author Last name, Year, cited in Secondary Author Last name, Year, Page no.)

Example:

• Seeberg (2013, p. 160) cites Waltham's work on migration (2010)...
• (Waltham, 2010, cited in Seeberg, 2013, p. 10)...

Still unsure what in-text citation and referencing mean? Check here.

Still unsure why you need to reference all this information? Check here.