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APA Style

Basic elements of references

A reference consist of four reference elements answering four questions.

WHO is responsible for this work?

Author: The author element of the reference includes whoever is responsible of the work. An author may be an individual or individuals, a group (government agency, organization, institution, etc.), or a combination of people and groups. Use a comma to separate the authors and use an ampersand (&) before the final author´s name. Provide the authors surname and initials for up to and including 20 authors. For work with more than 20 authors, include the first 19 authors´names, insert an ellipsis, and then add the final author´s name.

WHEN was it published?

Date: In a reference, the date refers to the date of publication. Usually just a year, but sometimes it needs to be more specific: year and month; year, month and day; year and season; or range of dates.

WHAT is this work called?

Title: The title is written in sentence case (mostly lowercase). Capitalize the first word of the title, the subtitle and proper nouns. After the title you can add a bracketed description, usually for works that are not text to describe the type of document being cited, for example video, podcast and artwork.

WHERE can I retrieve the work?

Source: In a reference the source indicates where readers can retrieve the cited work. The source information depends on document type, and usually consist of a periodical title, publisher or a website name plus a DOI or URL. When the author and publisher/website names are the same, omit the publisher from the source element to avoid repetition.


The reference list

The reference list is placed at the end of the work starting on a new page and includes all materials used in the text. The references are arranged in alphabetical order by their entries, i.e. the author(s) or the organization. According to APA, the reference list is not divided into different categories. If the same author has several publications, they are sorted in chronological order, with the earliest first. When multiple references have an identical author and publication date, include a lowercase letter after the year. If the year is missing, write n.d. for no date.


Digital object identifier (DOI) is a persistent identifier given to electronic documents that consists of an alphanumeric string.

  • Include a DOI for all works that have a DOI, regardless of whether you used the online version or the print version.
  • If an online work has both a DOI and a URL, include only the DOI.
  • For works without DOI from most academic research databases, do not include a URL or database information. The reference should be the same as the reference for a print version of the work. 
  • For works without DOI from websites (not including databases), provide a URL in the reference as long as it will work for readers.
  • Present both DOI and URL as hyperlinks (i.e., beginning with "http:" or "https:"). Because a hyperlink leads readers directly to the content, it is not necessary to include the words "Retrieved from" or "Accessed from" before a DOI or URL. Make the hyperlinks live if the work is to be read online.
  • When a DOI or URL is long or complex, you may use shortDoi service or TinyURL and shorten it.
  • Do not add a period after the DOI or URL.

Other alphanumeric identifier such as ISBN or ISSN are not included in a APA Style reference. Please visit APA Style for more information about DOI and URL.

Retrieval dates

Include a retrieval date only if the work is unarchived and designed to change over time. The majority of references do not include retrieval dates. References that might need a retrieval date is for example a dictionary entry designed to change over time, a frequently updated webpage, an unarchived Wikipedia article or a map generated from Google Maps.


Plagiarism is the act of using someone else´s work, words, ideas or images and presenting them as your own without providing a correct reference to the source. Failing to acknowledge other people's work and effort violates ethical standards in scholarship and may lead to disciplinary actions.

To avoid plagiarism, always provide a reference to the source whenever you:

  • paraphrase
  • directly quote words of others
  • refer to data or datasets
  • reprint or adapt a table or figure


A paraphrase means that you restate another´s ideas in your text with your own words. Paraphrasing allows you to summarize, interpret and highlight the most significant information for your own work. It is important that you cite the source you paraphrase so that the reader can distinguish between your arguments and those of the original text. When you paraphrase, cite the original work using the narrative or parenthetical citation formats (more information about citation you find under In-text citation).

Although it is not required to provide a page number in the citation, you may include one (in addition to the author and year) in cases when it would help readers locate the relevant passage within a long work (e.g., a book).


Abbreviations in text

When you first use a term that you want to abbreviate in the text, present both the full version of the term and the abbreviation. Avoid both overusing and underusing of abbreviations, according to APA Style a abbreviation should be used at least three times. For fewer mentions than three, present the full version of a term to avoid confusing the reader. However, always use an abbreviation for a long familiar term as American Psychology Association (APA) if it is more likely to be clear for the reader. Once a term have been abbreviated, the abbreviation is used consistently throughout the text.

Some abbreviations are so common that do not need any explanation, for example abbreviations listed as terms in the dictionary (eg. AIDS), Latin abbreviations such as et al., metric unites and time abbreviations. Note that the abbreviation "ibid" is not used in APA Style.


More information about abbreviation in APA Style please visit: