If you are citing two authors with the same surname, who have published in the same year, you can include their initials to differentiate between them.
Example: It is important that students develop academic skills as soon as possible during their HE course (Williams, N., 2013, p.12), otherwise students are likely to fall behind as they progress through their course (Williams, E., 2013, p.30). Therefore, academic skills should be embedded in first year courses at University.