Overview: In this section you will expand the topic you selected in the previous section with annotations about possible sources of information and likely locations.

Possible sources of scientific literature: The sources of information fall within these four categories reference, primary, secondary, and  web-based.

Reference Materials:
Reference materials of many types and formats exist. One of the most popular is one that you have grown up with: the phone book. You consult it constantly to obtain so many quick facts-- phone numbers, addresses, area codes, the names of government offices, and more.
Other kinds of reference materials include, but are not limited to, dictionaries, encyclopedias, almanacs, atlases, directories, and bibliographies. These may be paper, CD-ROMs, or even available on the World Wide Web. You're probably familiar enough with these types of materials to realize that reference sources are the things to consult to get answers to brief, factual kinds of questions and background information.

Why Use Reference Materials?
Reference materials are a great starting place for exploring a topic. Definitions, overviews, chronologies, facts, and biographies are some of the types of information found in reference works. Science encyclopedias and dictionaries describe the specialized language and history of the sciences in greater detail than general encyclopedias. Entries in specialized science encyclopedias can provide you with more than just a quick definition of a topic. You may find in such sources a thorough history of a topic, with explanations of basic scientific concepts, and cross-references to other related topics.

Primary:
Primary literature presents results of original research in formats such as articles, pre-publication prints of articles, and conference proceedings. Of the sources in this category, you are most likely to find and use journal articles, whether traditional paper journals or those you will find online. When you see the word "article," don't assume that you will be consulting Time or Rolling Stone to find primary materials. True, those publications carry many articles, but the type you want will be found in scholarly and academic journals like Nature and the Journal of Experimental Biology. These articles contain original data and have been "peer-reviewed" by scientists familiar with the area being researched.

Why Use Primary Literature?
Use journal articles to learn the latest results of fairly specific scientific studies. Journal articles will also acquaint you with the names of scientists working in particular areas and lead you to related articles cited in the bibliography. The information you'll find in primary literature is more focused than that found in secondary literature.  

Secondary:
Secondary literature includes books, annual reviews, textbooks, and some periodicals. These sources differ from reference materials in at least one important way: secondary sources, like reference materials, may answer factual questions; however, they also present background information and summarize results of scientific work so that you can read the full range of thinking on a particular topic. Secondary literature does not present the most current scientific information, which is found in primary literature.
Articles in science periodicals such as Discover and Science News are considered secondary literature because they don't present the results of original research, instead such articles synthesize and summarize descriptions of previous scientific work--which makes secondary literature very useful for you.

Why Use Secondary Literature?
Use annual reviews, textbooks, review articles in science periodicals, and books on scientific topics to gain detailed knowledge of a field, to learn about the historical development of a concept, and to become familiar with major researchers in an area of science. The secondary literature sources list gives just a few of the titles of this sort available in the library. You can find more secondary sources by using the Tufts Online Catalog, finding a relevant source, and then browsing the book stacks in the call number area where you located the first relevant source. Bibliographies in reference materials may also point you to secondary sources.  

Web-based:
World Wide Web resources include reference materials, primary literature, and secondary literature. In other words, the Web is a huge library of electronically-presented information of all sorts. A word of caution: just because you found it on the Web, don't jump to the conclusion that it is more authoritative than a similar paper document. Always make sure that you evaluate the material you find on the Web.
Traditional publishers are converting print sources to the Web--often for a fee. For example, the UIUC Library subscribes to Britannica Online, the Web version of the venerable Encyclopedia Britannica. You'll also find scientific information offered on sites mounted by professional societies and biology departments. Such sites may offer free links to datasets, electronic journals, online reference sources, images, and summaries of research projects. On innovative sites, you'll find resources that are impossible in print: simulation models, animated images, and searchable datasets.

Why Use Web Resources?
Web sites can offer timely news on scientific developments, easy access to electronic journal articles, and access to materials that can't be displayed in printed format. In fact there are examples from the whole range of scientific literature on the Web. However, resources on the World Wide Web are not a substitute for the traditional primary, secondary, and reference literature sources described in this tutorial. Web sources may be difficult to locate and must always be carefully evaluated.

STEP 2: Refine your list of possible sources - prioritize and reorder
This step helps you organize your search in an efficient way:
            1. revise the list you just created
            2. assign a priority to each item, use distinct numbers,
            Priority here is a subjective measure; it could indicate level of urgency or importance.
            In the example below, priority is taken as search order, meaning, the item that is assigned #1 is the one that we need to search first
            3. reorder the list according to priority from highest to lowest