Primary sources are the original descriptions of experiments, observations, or theory. This material is most often found in journal articles, but may also be found in proceedings of symposia and the technical bulletins of various agencies. Secondary sources (review articles, texts) are useful in familiarizing yourself with the field and as an aid in finding the original material. Do not, however, take another reviewer's conclusions on the primary sources as the last word, your interpretations may be different. Cite another reviewer's conclusions in your own paper if you wish, but don't cite a finding of a primary source unless you have reviewed the source yourself. Also, when evaluating a primary source don't rely solely on the abstract: check the results and see if you agree with the author's conclusions. Be critical, it is your job to examine the area of your review in a new light. One of the best ways to begin locating the primary sources in the area of your review are the databases available over the Library network, but don't rely on these alone, they are not omniscient! Once you have found several recent papers in the area, start looking up their references, then check the references in those papers, and so on; soon you will have a good feeling for the people, the pattern of research, and the work to date in the field. Examples of Primary Sources: Transactions of the America Fisheries Society, Journal of Fish Biology, Comparative Biochemistry and Physiology.
Many failures in term papers come from trying to review to much. A good, thorough review of primary sources takes time and choosing too broad a topic will result in an unfinished or superficially treated project. For example, don't try to write a complete, primary review of the "Hormones of Fishes" in ten pages; a more suitable topic would be "Gonadotropins of Teleosts". This doesn't mean you should neglect the supporting material. You need knowledge of that to write a good review, but you can rely on secondary sources for the peripheral information. Thesis reviews, of course, tend to be more inclusive than term papers, but the general approach is the same: rely on secondary sources for the base and then narrow in on the primary sources of direct concern to your research.
Too many inexperienced reviewers simply paraphrase the finding of each primary source one at a time and leave it at that. The result is a list of summaries, not a review. Point out similarities, conflicts, and unanswered questions among the primary sources. What are the trends? What research need to be done next? Don't be afraid to speculate, but substantiate your speculation and label it as such.
Bad Example:
Bluegills taken from a number of habitats throughout North America were found to have green blood; all samples were obtained by a syringe (Lepomis et al. 1982). Pomoxis and Centrarchid (1991) sampled adult white crappie from a number of southern ponds using a syringe and reported all to have black blood. Micropterus (1967) used a meat grinder to take blood samples from largemouth bass and found no blood of any color. Black blood was reported from largemouth bass in a Wisconsin lake when a syringe was employed (Salmoides 1977).
Good Example:
There is variation in blood color within the sunfish family. While crappies and largemouth bass have black blood (Salmoides 1977, Pomoxis and Centrarchid 1991), bluegill blood is green (Lepomis et al. 1982). An early report of an absence of blood in black bass (Micropterus 1967) is probably attributable to the use of a meat grinder as a sampling tool. Later work on demonstrating black blood in bass was confined to a single lake (Salmoides 1977) and is yet to be confirmed in other habitats, though no geographically based differences in blood color have been found in other members of the sunfish family.
Whenever you state information that you did not discover on your own or that is not common knowledge (". . since the sky is blue") you must attribute it to a source. The source in most cases is the primary literature. The style that most journals in our field use is author and date in the text (see examples above) and a complete citation in the Literature Cited section at the end. Literature Cited section is just that, do not put references in the Literature Cited that are not cited in the text and conversely be sure that all citations in the text are represented in the Literature Cited. Citation Examples: Different journals use slightly different (e.g. whether journal tiles are capitalized), here are examples of acceptable style.
Journal, Article
Strange, R.J., and J.J. Cech, Jr. 1992. Confinement stress and reduced swimming performance in striped bass. Transactions of the American Fisheries Society. 121(2):206-210
Technical Chapter in Edited Book
Fleener, G.G. 1975. Harvest of smallmouth bass and associated species in Courtois Creek. pp 250-256. In R.H. Stroud and H. Clepper, eds. Black bass biology and management. Sport Fishing Institute, Washington, D.C.
Published proceedings
Ensign, W.E., J.W. Habera, and R.J. Strange. 1989. Food resource competition in southern Appalachian brook and rainbow trout. Proceedings of the Annual Conference of southeastern fisheries and wildlife agencies. 43:237-247.
Thesis
Strange, R.J. 1975. The effects of herbicides on primary productivity, phytoplankton dynamics, and water chemistry of a aquatic system. Masters thesis. University of Tennessee, Knoxville.
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