Peer reviewed material is material published in scientific journals (or other types of journals). These articles have been published in these journals only following review of the articles by other scientists who assess the quality and validity of the material.
News articles and websites are not peer reviewed and anyone can right anything there whether it is true or not. In scientific essays you should focus on referencing peer reviewed material first and foremost before utilising other material.
Sample paragraph showing multiple references:
“TLR3 recognizes viral dsRNA and endogenous dsRNA derived from necrotic cells during inflammation (11, 12). In humans, defective TLR3 function has been associated with enhanced susceptibility to viral infection and in particular, herpes simplex encephalitis (13). Recently, a functional TLR3 polymorphism, Leu412Phe (TLR3 L412F, rs3775291) was described which results in attenuated NF-B- and IRF3-signaling in affected cells (14). TLR3 412F has also been shown to confer protection against geographic atrophy in macular degeneration by attenuating TLR3-induced retinal epithelial cell apoptosis (15).”
References should be used throughout the essays. The above piece is in Vancouver Style. Other referencing styles can be found here. Details of what Vancouver style is and how to use it for different types of references can be found here:
- Using another author’s words without proper citation
- Using another author’s ideas without proper citation
- Citing a source but reproducing the exact word without quotation marks
- Borrowing the structure of another author’s phrases/sentences without giving the source
- Borrowing all or part of another student’s paper
- Using paper-writing service or having a friend write the paper
Avoid using significant amounts of quotes to in your essay as this is not appropriate. Put things you’ve read and understand in to your own words.