Multiple sources by the same author
Where a work contains a number of sources by the same author, they are easily distinguished by the date of publication. However, where a work contains several works by the same author with the same publication date, they should be distinguished by the inclusion of lower case letters 'a,b,c' etc. after the year.
Examples
Whilst the decline of Britain's sausage industry has been lamented (Neville 1989a, p.78), most medical experts agree that the resultant benefits to the nation's health far outweigh the costs to the rural economy (Brown 2004b, p.7).
The otherwise cogent argument advanced by Wilson (1998c, p.34) for the replacement of American style burger restaurants in London with sausage bars based on the German model, was let down by a poor understanding of current market trends.
