Different Kinds of Sources

The understanding that original research is based on first-hand data (that is, not on someone else's comments or interpretations of that data), makes it necessary to distinguish between different kinds of sources.

In this section, the difference between primary, secondary and tertiary sources is explained.

Source and reference

The source is the text or other work that provides the information that is being used (whereas the actual mention of the source that is being used is called a reference). To some extent, these terms are synonymous; in several reference styles, the list of sources used in an academic text are called 'References,' for instance.

When discussing the actual function of the reference in the written text, however, it may be useful to distinguish between the terms 'source' and 'reference'.

Example: Difference between source and reference (click to expand/contract)

In the following two examples, the sources that have been used are identified, as well as the references that are provided.

The first extract comes from a conference paper in the field of Theology and Religious Studies. The reference given here is in the form of a direction to a biblical passage, and the source (that is, where the passage quoted is to be found), is the New Testament Book of Matthew.


At the beginning of each of the four Gospels we meet a man who challenges us to get baptized: John the Baptist. In the Gospel of Matthew he cries out: "Repent! The kingdom of heaven is near" (Matth. 3:2).  

(Borgehammar, 2009, p. 1)

The second example comes from a Master's degree dissertation in Computer Science about structured testing processes. In the extract below, the reference is "Boehm (1976)", and the source is a certain journal article, written by Boehm and published in 1976, the full details of which are given in the list of references.


In many projects, testing-related costs count for up to 50% of the total software development cost. Boehm (1976) argues that these large costs stem from introducing testing too late in the process, and that these costs could be lessened if a defect could be detected and fixed at the same stage as it is introduced. This praxis needs good planning and a structured test plan.  

(Färnstrand, 2008, p. 16)

In order to use sources efficiently and in a correct manner, writers must be able to identify the nature of each source and the reason for using it. By clarifying to themselves what kind of use they make of different kinds of sources, writers will be able to distinguish between their own contribution and the argument expressed by the sources that are being used.

It should be noted that the distinctions that are made below may be more relevant in some fields than in others. Students are advised to discuss the use of sources with their supervisors and with the library staff at their departmental library. Note, though, that all writers need to be aware of the importance of originality, in the sense of first-hand results, in scholarly writing.

How to choose sources

One of the central learning outcomes of university studies is the ability to assess information. When writing, students train their ability to decide whether a source is appropriate and how to use it.

The University Library is a valuable resource for students in need of help concerning the choice of sources:

Common scholarly publication forms (click to expand/contract)

Research writing is published in various forms. Some common types of publications are listed here. Depending on discipline, some publications forms are more common and relevant than others.


An anthology is a collection of texts (or other created works) on a specific subject that are published (or otherwise presented) together.

Conference proceedings

The volume of papers which are published in connection with conferences is often referred to as proceedings. Such a publication usually consists of articles based on the plenary lectures and on a selected number of participating papers.

Journal article

An article is a text that has been published in a journal (periodical), magazine or newspaper. There are different kinds of scholarly articles; apart from original articles (articles that present new, original, research), there are review articles, letters and editorials, for instance. Original articles can be divided into, for instance, methodological articles, theoretical articles and case studies. For further information about different kinds of articles, see the AWELU section called


A monograph is a text (often book-length, but could also be a long article) that treats one specific subject.


A periodical is a journal that is published regularly (periodically = 'at regular intervals'). The terms 'journal' and 'periodical' are often used synonymously.

Thesis / Dissertation

A thesis (dissertation) is an extensive research paper that is written as partial fulfilment of an academic degree. In reference styles, the abbreviations 'Diss.' or 'Unpubl. Diss.' can be used to identify dissertations in the reference list, unless they have been published in book form by a publishing company or university press.

Note that most reference style manuals have been published in the US and therefore use the American English 'dissertation' for 'doctoral dissertation,' whereas the word 'thesis' or 'doctoral thesis' is more common in British English. Read more about this in

Additional terms in connection with publication forms:

Annotated edition

The word annotation in 'annotated edition' indicates that the text has been provided with explanatory notes, comments or other kinds of extra material. This is common in republications of old texts, for instance. If the text is annotated, this will be indicated in the title.

Editions / Reprints

Works may go through several editions and reprints. If it is reprinted, unless stated otherwise, no changes are made to the text itself, but a second (third, etc.) edition will indicate that the text has been updated or otherwise changed.

Primary, secondary and tertiary sources

Sources can be divided into three types, depending on their proximity to the subject of study:

Primary sources

A primary source is usually a document or result that is being reported first hand. In other words, primary sources are original sources, not interpretations made by someone else.

The following often function as primary sources:

  • works of fiction
  • diaries
  • interviews
  • official documents, such as census data and legal texts
  • objects, such as archaeological findings
  • numeric data
  • corpora
Secondary sources

Secondary sources value, discuss or comment on the primary source, or on sources analogous to the primary source that is being analysed.

The following are examples of such secondary sources:

  • research articles
  • biographies
  • monographs
Tertiary sources

A tertiary source is a source that summarises or compiles facts and knowledge produced by someone else. Tertiary sources are often some kind of assemblage of primary and secondary sources. They are convenient for quick access to summarised facts, but not all sources that belong to this category are considered suitable for scholarly writing. For instance, it is usually not acceptable to use compilations of facts instead of reading the original sources. Therefore, students writing essays are recommended to consult their teachers on the suitability of using tertiary sources in their writing.

Sources that would be regarded as tertiary sources include:

  • textbooks
  • study guides
  • encyclopaedias and wikis
  • indexes and other classification systems

A note of caution

It should be noted that the distinction between primary, secondary and tertiary sources is not a fixed one. For instance, in an analysis of an encyclopaedic article, that text would be regarded as a primary source, and in a review of a scholarly monograph, the text under scrutiny would be seen as a primary source, although it would be used as secondary source material under other circumstances. Students are advised to check with their teachers what types of sources are expected and accepted.

Examples of sources used in different disciplines

Example: Bachelor's degree project in English (click to expand/contract)

For her bachelor's degree project in English Literature (Faculty of Humanities), a student studied the concept of 'otherness' in Nadeem Aslam's novel Maps for Lost Lovers.

The primary source for this study was the novel itself, and the secondary sources consisted of critical studies on post-colonialism and on the concepts of 'race' and 'otherness,' and of articles discussing the particular novel. 

  • Bengtsson, M. (2008) Visualising otherness in Maps for Lost Lovers by Nadeem Aslam: Discussing othering in and through Literature (Bachelor degree project). Lund University. [Access degree essay] (PDF)

Example: Master's degree dissertation in International Development and Management (click to expand/contract)

In a master's degree thesis in International Development and Management (Faculty of Social Sciences), the focus was on water management in Jordan.

The primary sources for this study consisted of a set of interviews and group discussions conducted on site in Jordan, and the secondary material consisted of studies on central issues such as water demand and water management, for instance, and on aspects of development and gender.

  • Ellefsen, A. & Kolic, H. (2010). Let it rain: A case study of community-based water management and rainwater harvesting in Bayoudah, Jordan. (Master thesis). Lund University, Lund. [Access via LUP]

Example: Doctoral thesis in Applied Nutrition and Food Chemistry (click to expand/contract)

In a doctoral thesis in Applied Nutrition and Food Chemistry (Faculty of Engineering), the focus was on acrylamide in potato crisps.

The primary data was generated from the experimental work carried out for the project, and secondary sources consisted of previous studies in the fields of food technology and chemistry.

  • Viklund, G. (2007). Acrylamide in Potato Crisps: A Three-Year Study on Swedish-Grown Potatoes. (Doctoral dissertation). Lund, Sweden: Lund University. [Access thesis via LUP]