Put all the references into Reference Manager software. You can store the references in different folders and this makes it easier to find and write up publications. I highly recommend this as it saves so much time and makes writing easier.
Definitely would advise using software such as EndNote or Reference Manager as Taz and Anon German have suggested. You can download your references directly from a data base (e.g. PubMed) into your library file then everything is at hand and it makes inserting citations and creating bibliographies in MS Word really easy. Your Uni will have these software packages. Best wishes.