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Library Essentials

New to NUS? Welcome to Library Essentials!

Here are some snippets of the digital information landscape to understand how to utilise information better for your assignments and research!

What is information and where does it come from?

The nature of the information gives us a clue about how fast it has been produced. Different sources of information churn out various information at different speeds, at the expense of information credibility and reliability. Watch this short video to find out more.

The most common way information is categorised.

Primary, Secondary or Tertiary sources

Primary sources of information provide original or firsthand information gathered by author(s). Examples include creative works, documents created during an event such as news reports, raw survey data, interview audio recordings, diaries, photographs and conference proceedings, or scholarly empirical research analysis and patents.

Secondary sources describe, critique, interpret or analyze information obtained from primary sources.  Examples include monographs, textbooks, commentaries and scholarly review articles.

Tertiary sources compile and summarize mostly secondary sources with a broad perspective.  Examples include reference publications such as encyclopedias, bibliographies or handbooks.

Whether a source is primary, secondary or tertiary also depends on the usage context.

For more information, see this pdf summary by Virginia Tech University.

When using information sources to backup your research arguments, it is frequently recommended to use only scholarly sources. What are they, and how do scholarly sources differ from other types of information?

Scholarly and Professional sources for academic research

Scholarly sources of information include original in-depth information or data about a specific topic for scholarly purposes, targeted at researchers, students and scholars. The authors are usually researchers with subject expertise, usually employed by educational or research institutions. These in-depth information sources usually include technical information and specialized terminology, tables, graphs, and appendices. They also include a complete list of citations following a particular style standard for all sources referred to and the author(s)’ credentials. 

A panel of experts in the field would peer-review or critically evaluate the work before circulation (Note that peer-review does not include supervision and evaluation of dissertations and theses). The works are then published by academic institutions, professional associations and/or commercial publishers.

Examples of scholarly sources include journal articles, monographs (scholarly books), conference proceedings, academic databases/platforms, theses, market research reports, and standards. For more information on the examples, click here.

Through NUS Libraries, you can find scholarly sources on our library shelves and catalog (LINC). Scholarly sources can also be found online using the library search engine FindMore@NUSL and Google Scholar. A few starting recommendations for multidisciplinary databases would include Scopus and Web of Science, and the major aggregators like ProQuest, OvidSP and EBSCOhost. Aggregators refer to platforms that contain multiple databases, commonly from various disciplines.


Trade/professional sources of information include information updates, data, trends and opinions about a particular discipline targeted at professionals within the discipline or industry for professional support and application, targeted at trade professionals and interested parties. The authors are usually trade professionals or persons with expertise, credentials may or may not be shown. These sources' presentation could be similar to scholarly sources', with a lesser degree of complexity, and including some pictures and targeted advertisements. Sometimes a list of references that is optional is included, but it is optional.

Before publishing, the information may be edited by editorial staff who may be subject experts evaluating the workThe works are then published by professional or trade groups.

Examples of these sources include periodical publications such as newsletters, reports, articles and magazines of trade organizations.

Recommended online databases for trade publications are ABI/Inform, Business Source Premier, Factiva and Scopus. These sources of information may be useful for academic research for market and industry reports.

Peer reviewed articles

Peer-reviewed articles are highly esteemed in academia, but what does it mean? Simple explanation in the video below:


What about government documents, or working papers, or theses?

Grey Literature

According to the 12th International Conference on Grey Literature in Prague in 2010, 

"Grey literature stands for manifold document types produced on all levels of government, academics, business and industry in print and electronic formats that are protected by intellectual property rights, of sufficient quality to be collected and preserved by libraries and institutional repositories, but not controlled by commercial publishers; i.e. where publishing is not the primary activity of the producing body."

Grey literature is thus a catch-all term for output produced by academic, business, government, or research institutions that are not published formally/commercially but are important information sources for academic research, such as in the discipline of public health.

Examples of grey literature include conference abstracts, presentations, proceedings; regulatory data; unpublished trial data; government publications; reports (such as white papers, working papers, internal documentation); dissertations/theses; patents;  and policies & procedures.

For more information on grey literature, examples and where to find them, click here.

Popular sources of information include news updates, current events, secondary research discussion, public interest topics, personal narrative and opinions targeted at the general public. The authors are usually journalists or writers or freelancers with or without expertise, and their credentials may or may not be shared. These sources usually include layman language for easy understanding, pictures, advertisements and diagrams. They may or may not include source references, which may be brief and/or unformatted if available.

Before publishing, the information may be edited by editors who are often not subject experts for formatting, layout, subject and language, or may not be edited at all. The works are then published by commercial publishers.

Examples of popular sources include news articles, opinion pieces, blog entries, discussion forums, books, magazines and news databases. Citizen journalism, where individuals of the general public generate news and information content via collection, analysis and dissemination online e.g. social media sites, is increasingly accepted as a popular information source.

Through NUS Libraries, you can find magazines and newspapers on our library shelves and catalog (LINC). Recommended online news databases are Factiva, Nexis Uni and NewspaperSG. These sources of information may be useful for academic research under the right context. For more information on online news provision by the library, click here.

A different set of challenges are faced when dealing with popular sources as the authorship, accuracy and purpose of an information source e.g. a commentary or social media post, can vary extensively.

An infographic below outlines how a popular source i.e. media can be evaluated for use in the right context.