Few writers in science and technology pay sufficient attention to the citations and references in their works. The impression is too often given that citations and references are of secondary significance to the subject matter treated in the text. This attitude is not only wrong but a disservice to the cause of science, as you will soon appreciate in this unit.

You have a responsibility to learn, as early as possible in your career, why it is important to take citations and references as seriously as the text material in all types of writing that you undertake. The application of that learning will bear much dividends in a better organisation of your work, in a greater appreciation of your worth as a scientist, and in a better understanding and appreciation of all aspects of human knowledge. The last point is particularly important because science and technology must always be perceived as only a slice—albeit an important slice – of the corpus of human knowledge.

This unit, then, is presented in five parts. Part one describes the antecedents of the reference tradition in science, a tradition that is heavily indebted to the humanities. Part two gives you some basic rules to follow in citing the literature handled in your writing. Part three describes the major features of bibliographic and reference styles that you need to know, and the last part describes the name and date citation system that is commonly used in scientific writing. The usual Conclusion, Summary, References, and a self-assessment assignment complete the unit.


At the end of this unit, you should be able to:

  1.  recognise and appreciate the main attributes of the citation and reference tradition in science 
  2. name and describe the three basic rules of citing the literature of science 
  3. describe the major characteristics of bibliographic and reference styles 
  4.  recall and correctly use the name and year system in making citations and listing references. 


3.1 The Citation and Reference Tradition in Science

The reference tradition in science derives from the principle of citation indexing which is based on the simple concept that an author’s references to previously recorded information should identify much of the earlier work that is pertinent to the subject of his present document. These references are commonly called citations, and a citation index is a structured list of all the citations in a given collection of documents. Such lists are usually arranged so that the cited document is followed by the citing documents.
The first practical application of this concept was Shepard ‘s Citations, a legal reference tool that has been in use since 1873. Shepard’s Citations owes its existence to the factthat American law, like English law, operates

under the doctrine of Stare Decisis. Stare Decisis means that all courts must follow their own precedents as well as those established by higher courts. The precedents are the decisions handed down in previous cases.

To try a case under Stare Decisis, a lawyer must base his argument on previous decisions regarding a similar point of law. Before presenting the previous decision as a precedent, however, the lawyer must make sure that the decision has not been overruled, reversed, or limited in some way. Shepard’s Citations enables the lawyer to do this with a minimum of trouble.

As the doctrine of Stare Decisis provided the logic for Shepard’s Citations, so did the “reference tradition”‘ provide the rationale for citation indexes in science. The scientific tradition requires that when a scientist or technologist writes or publishes a paper, he should refer to earlier articles which relate to his theme. These references are supposed to identify those earlier researchers whose concepts, methods, apparatus, etc., inspired or were used by the author in -developing

his own paper. Some specific reasons for using citations are as follows:

  1.  Paying homage to pioneers 
  2.  Giving credit for related work 
  3. Identifying methodology, equipment, etc 
  4.  Providing background reading 
  5.  Correcting one’s own work 
  6.  Correcting the work of others 
  7.  Criticising previous work 
  8.  Substantiating claims 
  9. Alerting researchers to forthcoming work 
  10.  Providing leads to poorly disseminated, poorly indexed, or uncited work 
  11.  Authenticating data and classes of fact- physical constants, etc 
  12. Identifying original publications in which an idea or concept was discussed 
  13.  Identifying the original publication describing an eponymic concept or terms like Hodgkin’s disease, Pareto’s Law, Friedel-Crafts Reaction 
  14.  Disclaiming work or ideas of others 
  15. Disputing priority claims of others. Etc., etc. 

In the early 1950s, the availability of this built-in system for linking scientific papers began to receive attention as the possible foundation of an indexing system for the scientific literature. Today, citation indexing has become a significant part of the literature of science, thanks largely to the pioneering efforts of Eugene Garfield and the Institute for Scientific Information in the USA.

It is very important that you both understand and appreciate the significance of this tradition in enhancing the quality of science. Your technical report or scientific paper is not an isolated work; it is part of a long established and continuing tradition of science. You must, therefore, do everything within your powers to maintain and even strengthen the tradition. The guidelines provided in this unit and in Unit 3 are designed to help you maintain and strengthen this cherished tradition.

3.2 Basic Rules to Follow

There are three basic rules to follow in handling the citations and references of your technical reports and scientific papers. The first is by far the most important, and you should always recall it in your citations and references, as well as in the citations and references of others. Here, then are the three rules:

a. Rule I: A fundamental objective for citing another work, or for referring to it in your own work, is to identify it with a sufficient number of unique features that it cannot possibly be confused with another work, no matter how similar. This ‘verification objective’ needs to be fully understood and
appreciated by all scientists. Because so much scientific work is published or unpublished every day, keeping track of what has been done in science is a daunting task. Therefore, everything possible
must be done to identify each piece and the citing and referencing
procedure is a necessary aspect of attaining that identification objective. You must identify each piece in your work by listing all its _unique features such that it cannot possibly be confused with
another work, no matter how similar.
b. Rule 2: You should list only significant, published and unpublished references, but you must not allow references to unpublished data, papers in press, abstracts, and other secondary materials to clutter your References.
A long list of References does not necessarily confer authority respectability on your work. On the contrary, it may expose you as being unable to select what is really necessary from a large pool of
available works.
c. Rule 3: Take time to check all parts of every reference against the original publication, before the report or manuscript is submitted, and perhaps again at a later stage, say, the page-proof stage.
References obtained from electronic media, such as the Internet, may not be available for physical inspection. In which case, your report or paper should say so, unequivocally. You should never
leave the reader in any doubt about whether or not you, as author, can vouch for the accuracy of all the parts of a citation in your work. 

And you should also remember this:

  1. there are far more mistakes in the Literature Cited 

(References) section of a paper than anywhere else.

3.3 Bibliographic and Reference Styles

There are many good bibliographic and reference manuals that have been published and regularly updated by major organisations and institutions. These manuals are designed to remove completely the burdensome issue of deciding how you should cite a book, chapter in a book, journal article, conference paper, etc., in your work and then arrange them at the end to satisfy Rule 1 given to you above. The United Nations Organisation’s Dag liarmmarksjold library, for example, has such a manual which many writers have used for decades. The British Museum and the Library of Congress have published similar manuals for use by authors.

All that you are required to do is adopt one of such manuals as your working tool for citing any type of published or unpublished work within your text, and for arranging all the references at an appropriate place(s) in the work. In other words, your adopted manual will show you how to cite as well as what to include (and exclude) in order to make your citations and references both complete and consistent. You obviously have to learn to be familiar with your adopted manual, so that citing and referencing will become virtually automatic throughout your career.

But you sometimes have to conform with other styles preferred by other authorities with which you have to do business. Journals are the most obvious example of such authorities because ‘publishing in scientific journals’ is such an important activity in science and technology.

Journals vary considerably in their style of handling citations and references. One person looked at 52 scientific journal and found 33 different styles for listing references. Some journals print the titles of articles and some don’t. Some insist on inclusive pagination, whereas others print first pages only. What do you do when faced with such a situation?

The wise thing to do is to write out all your references in full at all times,irrespective of the journals or authorities to which you intend to submit your manuscript. There are several advantages in cultivating this habit including the following:

  1.  Your manuscript has all the needed information. It is easy to edit out information; it is much more difficult (and less certain) to add bits of bibliographic information, such as article titles or ending pages, to a reference list that is deficient in such areas. 
  2.  The journal you selected may reject your manuscript, resulting in your decision to submit the manuscript to another journal, perhaps one with more demanding requirements. 
  3. It is more than likely that you will use some of the same references again, in later research papers, review articles (and most review journals demand full references), technical reports, and books. In view of the above, you should adopt the, fullest, possible bibliographic and reference style in all your writing. Since your knowledge of what you learn in this unit will be most readily applied in dealing with scientific journals, it would be useful for you to know the three general ways in which journals cite references). The three ways are usually referred to as 

“name and year”, “by number from alphabetical list,” and “by number in order of citation.” Only the “name and year”, approach will be covered in this unit. In Module 3 Unit 3, the two other approaches will be described for you, as well as other considerations in citing and arranging references. 

3.4 The Name and Year System

The name and year system (often referred to as the ‘Harvard system) was very popular for many years and is still used in many journals, although that system is not as widely used as it once was. Its big advantage is convenience to the writer. Because the references are unnumbered, references can lie added or deleted easily. No matter how many times the reference list is modified, “Onwumechili and Ette (1964)” remains exactly that. If there are two or more “Onwumechili and Ette (1964)” references, the problem is easily handled by listing the first as “Onwumechili and Ette (1964a),” and the second as “Onwumechili and Ette (1964b),” etc.

The disadvantages of the name and year system relate to readers and publishers. The disadvantage to the reader occurs when (often in the Introduction) a large number of references must be cited within one sentence or paragraph. Sometimes readers must jump over several lines of parenthetical references before they can again pick up the text. Even two or three references, cited together, can be distracting to the reader. The disadvantage to the publisher is less serious but not insignificant: increased cost. When “Owumechili, Ette, and Awe (1962)” can be converted to “(8)”, considerable typesetting and printing cost savings can be realised.

Because it is the norm, rather than the exemption, for scientific papers to have multiple authors, most journals that use the name and year approach to referencing have an “et al” rule. Most typically, the rule works as follows: Names are always used in citing papers with either one or two authors, e.g., “Onwumechili (1962),” “Onwumechili and Ette (1964),” If the paper has three authors, list all three the first time the paper is cited, e.g., “Onwumechili, Ette, and Awe (1962).” If the same paper is cited again, it can be shortened to “Onwumechili et al. (1962).” When a cited paper has four or more authors, it should be cited as “Onwumechili et al.(1962a)” even in the first citation. When it comes to the ‘Literature Cited’ or ‘References’ section, however, some journals prefer that all authors be listed (no mater how many); other journals cite only the first three authors and follow with “et al.” You should have no problem adapting to the requirements of any journal if, as you were advised above, you always write every entry in your ‘Literature Cited’ or ‘References’ in full.

Locate a standard textbook in your subject area(s). Examine the approach adopted by its author(s) in making citations within the text and in listing the citations at the end of the chapters of the books. If there is a ‘Bibliography’ at the end of the book, look it over as well. On the basis of what you have learned in this unit, try to answer the following questions:

  1. Is every entry full and complete? 
  2. Does the approach to citing references in the text help or hinder readers’ fluent reading of the text?
  3. Are there obvious flaws in the citations or references that you can correct?
  4. To what extent have the “three basic rules of citing the literature of science” been adhered to? 


It is important that every scientist knows and appreciates why and how citations are made in scientific texts. It is equally iinportant that the citations be properly and accurately arranged at the end of the text where the citations occur. Every written work must endeavour to perpetuate this noble tradition of science.

In order to help you understand and appreciate this tradition, the doctrine of Stare Decisis is explained to you, as well as how the principle has been applied to establish a pattern of citations and references in science and other areas of human knowledge. You are then given three basic rules for handling the citations and references in your technical reports and scientific papers. Then, the characteristics of bibliographic and reference styles are explained to you and you are advised to adopt a standard style in your scientific writing. Finally, the ‘name and number’ system, used by many journals in organising citations and references, is described for you with several examples.


At the end of unit, you have learned to:

  1. recognise and appreciate the major attributes of the citation andreference tradition in science
  2. name and describe the three basic rules of citing the literature of science
  3.  describe the major characteristics of bibliographic and reference styles; and
  4.  recall and correctly use the ‘name and year’ system in making citations and listing references. 


  1. Name and describe the three basic rules of citing the literature of science. 
  2.  Describe the major characteristics of bibliographic and reference styles. 
  3. What are the main attributes of the citation and reference tradition in science ? 


Not just projectandmaterials but the no.1 ultimate source to all your educational info resources and project materials of various discipline.


All research courses listed on our website is for educational and  Research  purpose, Locate your course title and access the research  materials. 

 The research courses comprises of two categories.  Note: success occur when opportunity meets preparation…go for success, go for the feature, study to show your self approve. 



VISIT FOR Available project topics and materials / view departments


Leave a Reply

Your email address will not be published. Required fields are marked *