You will need to critically analyse each source for how they contribute to the themes you are researching.
A literature review is an account of what has been published on a topic by accredited scholars and researchers.
These are more rigorous, with some level of appraisal: Source: Grant, M. Health Information & Libraries Journal, 26(2), 91-108.
A literature review means finding, reading and summarising the published research relevant to your question, in other words finding out what is already known about your topic.
Look at the following examples and see how the students summarise a number of studies and contrast differing findings.
Review Literature Thesis Conclusions Section
Also notice the use of evaluative language to show the student's evaluation of the previous research."Several studies [5, 6, 7] have reported the benefits of using boron solid sources over other types of boron diffusion source. On the contrary, Warabisako et al  demonstrated that obtaining high efficiencies with boron solid source was no easy task.
At university you may be asked to write a literature review in order to demonstrate your understanding of the literature on a particular topic.
You show your understanding by analysing and then synthesising the information to: Work out what you need to address in the literature review.
It could be from five sources at first year undergraduate level to more than fifty for a thesis. Keep a note of the publication title, date, authors’ names, page numbers and publishers. Each body paragraph should deal with a different theme that is relevant to your topic.
You will need to synthesise several of your reviewed readings into each paragraph, so that there is a clear connection between the various sources.