Re social networking sites useful for recruitment?(Facebook,twitter,linkedin)

I had one literature review. But my supervisor asked me to change it and write a new one. Because he said I should use something to compare. My dissertation topic is about the effect and usefulness of social networking on recruitment process. However, in the one that you are going to write, there should be relevant references about the age differences. Which age group uses social networking more, and for getting a job(recruitment). Mainly comparing age groups that use social networking for finding and applying for jobs. I want you to concentrate on mainly finding very related journals, books with recruitment via social networking. I am going to send you my previous literature review and another example literature review which it should look like. I will then send it to my supervisor to check.

Referencing Requirements:
I want you to do the literature review with very good and related references. And In the end, to tell me which 3-4 main books or journals are the most important ones for this topic. I ordered essays from here couple of times, and there were fake references used in one time, so please dont do that.