This is the Vancouver style for referencing, used at the Univerity of Portsmouth within the School of Pharmacy and Biomedical Sciences and the Radiography departments.
This guide is modelled on Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers (2nd edition). You may wish to consult this source directly for additional information or examples.
Advice can vary on this and it might be best to speak to your tutor. For academic work we recommend that if you haven't read the original source, you do not give the details of the original in your bibliography/reference list, you just list the item which you have actually read. The only place where you mention the original source is in your text itself where you need to be clear you haven't read the original by writing something like:
Smith discusses Brown's work highlighting the.... (15)
In your bibliography/reference list item 15 would give the details of the book by Smith which you have used.