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Reference Like a Pro: The 2024 Guide to APA, MLA, Chicago Styles, and Beyond

You’ve been led here because you know that reference is the backbone of academic writing.

Whenever you’re paraphrasing, quoting, or summarizing what someone else has said, you know you’ve got to cite your sources. It’s all about giving credit to the original thinkers behind your references and making sure you’re not just copying someone else’s hard work verbatim. Instead, you’re primarily learning from them and then giving them the acknowledgement for that idea or fact.

But here’s where it gets interesting – there’s not just one way to cite sources. It’s almost like choosing the right tool for the job.

And that’s where Guru comes in.

I’ll walk you through the major citation and reference styles like APA, MLA, Chicago, Harvard, Oxford, etc. and help you figure out how to correctly cite in your academic papers. I’ll break it all down in simple terms and give you practical examples. This way, you can easily pick the style that fits your writing needs the best.


Footnotes are little notes at the bottom of the page. They cite sources or comment on a specific part of the text. For example, if you want to add a comment that doesn’t fit in your paragraph, you can do so at the bottom with a footnote. In the paragraph, you can add a footnote symbol for reference.

Types of Citation and Reference Styles

Every university, academic association, and publisher handles citations differently, and they usually give an official guidebook to help you navigate this. There are three primary types of citations that you can use in your text: parenthetical, numerical, and note citations. Each has a unique style of referencing.

  1. Parenthetical: The author’s identifying information is enclosed in parentheses in such citation styles. Parenthetical citations have the author’s last name, page number, and publication date in parentheses. To give you an example: (Shelby, 2024).
  2. Numerical: These citations contain numbers in brackets or superscript that match to the full entries in a numbered reference list. For example: Marx’s work [1].
  3. Note: Note citations are provided in footnotes or endnotes, indicated by a superscript number in the text. For instance: Engel’s study1.


Citation and reference styles might seem a bit confusing at first, but they all share some common features. You’ll always mention the author’s name, the title of the work, and the publication year. In each style, these parts could be written in different ways.

Examples of Major Reference Styles

Parenthetical Reference Styles

1. APA (American Psychological Association)

APA citation style is your go-to in the field of social sciences. It neatly wraps the author’s name and the year of publication in parentheses right within your text. Then, in your References or Bibliography section, you’ll list all your sources with full details. This will help you follow specific formatting rules laid out by APA.

For example, if you’re citing a book titled Exploring the Cosmos by Alex Johnson, published in 2020, here’s how you would format this citation in APA style:

Reference Johnson, A. (2020). Exploring the Cosmos. Publisher Name.
In-text (Johnson, 2020)

Here, “(Johnson, 2020)” means that the information is sourced from Alex Johnson’s book published in 2020.


A bibliography or reference section is a list of sources referenced in a document, including books, articles, and other materials. It typically includes details such as author names, titles, publication information, and dates to allow readers to locate the cited sources. It is placed at the end of the paper.

2. MLA (Modern Language Association)

If you’re going into the humanities, you’ll likely find yourself using MLA style quite a bit. This style keeps things simple with the last name of the author and the page number in the in-text citation. This will take your readers straight to the source. When it comes to compiling your Works Cited or Reference page, you’ll detail each source’s full publication information.

Let’s say you’re citing a book titled Cosmos and Me by Taylor White, published in 2020. Here’s how you would format it in MLA style:

Works Cited White, Taylor. Cosmos and Me. Publisher Name, 2020.
In-text (White, 45)

In this example, the citation “(White, 45)” shows that the information is from page 45 of Taylor White’s book. This notation is used right in your text to clearly point to the source of the information, making it easy for your readers to see where your facts or ideas are coming from.

3. Chicago Author-Date

When you’re working in the natural or social sciences, you might often use the Chicago Author-Date style. This method neatly includes author-date citations right in your text – just in parentheses – to help your readers quickly pinpoint your sources. At the end of your work, you’ll compile a bibliography that lays out full publication details for each source.

For example, if you’re citing a book titled Journey Through Time by Emily Thompson, published in 2019, here’s how it would be formatted in the Chicago Author-Date style:

Bibliography Thompson, Emily. 2019. Journey Through Time. New York: Random House.
In-text (Thompson, 2019)


Just a heads up – don’t mix up the Chicago author-date citation style with Chicago notes. The former neatly tucks the author-date info into parentheses right in your text and pairs it with a reference list, while the latter opts for footnotes or endnotes and includes a bibliography at the end.

4. Harvard

Switching to the Harvard citation style, it’s quite similar to APA. In your text, you’ll put the name of the author and the year of publication. At the end of your paper, you’ll make a reference list with full publication information.

For example, if you need to reference a book called Secrets of the Ocean by David Walker, published in 2018, here’s how the citation would look in Harvard style:

Reference Walker, D. 2018. Secrets of the Ocean. London: Oceanic Press.
In-text (Walker, 2018)

In your writing, when you include an in-text citation like this: “Marine biology offers insights into the unique ecosystems of the oceans (Walker, 2018),” you’re indicating that the insights you’re discussing come from David Walker’s 2018 publication. The citation “(Walker, 2018)” neatly points your readers to the exact source where they can find more information, making your work transparent and well-supported.

5. ASA (American Sociological Association)

In sociology and related fields, you’ll often use ASA style. This system, developed by the American Sociological Association, simplifies citing sources by using an author-date citation system. Here, you’ll include the last name of the author and year of publication directly in your text, linking to a detailed reference entry in your bibliography or reference page.

For example, if you’re citing a book titled Global Societies by Laura Chen, published in 2021, here’s how the ASA citation format would look:

Reference Chen, Laura. 2021. Global Societies. Boston: Beacon Press.
In-text (Chen, 2021)

When you see “(Chen, 2021)” in your text, it’s clearly pointing out that the information comes from Laura Chen’s book, released in 2021.

6. APSA (American Political Science Association)

Switching over to APSA citation style, which is predominantly used in political science research, this method combines in-text citations with a detailed references list. In the text, you usually put the author’s name and the year of publication in parentheses. This tells your readers to look at the references section for more information.

For example, if you need to reference a book called Politics in the 21st Century by Michael Abrams, published in 2022, here’s how you would format it in APSA (American Political Science Association) style:

Reference Abrams, Michael. 2022. Politics in the 21st Century. New York: Academic Press.
In-text (Abrams, 2022)

 Here, “(Abrams, 2022)” means that the referenced material is from Michael Abrams’s 2022 work.

Numerical Reference Styles

1. IEEE (Institute of Electrical and Electronics Engineers)

In the realms of engineering and technology, IEEE style is your go-to for citing sources. This system uses numerical citations enclosed in square brackets, which correspond to a detailed reference list at the end of your document. This method keeps your writing sleek and the references easy to track.

For example, if you’re referencing a journal article titled Advancements in Artificial Intelligence by Sarah Lee, which was published in the Journal of Computer Science in 2023, here’s how the IEEE citation would appear:

Reference [1] S. Lee, “Advancements in Artificial Intelligence,” Journal of Computer Science, vol. 58, no. 4, pp. 204-210, 2023.
In-text [1]

In this scenario, “[1]” refers to the first source listed in your reference list, in line with IEEE standards.

2. Vancouver

In your medical or scientific research, you’ll find the Vancouver style quite handy. It’s similar to the IEEE style and uses numerical citations in the text, neatly enclosed in brackets, with a reference list at the end. You might notice that the format for each reference can vary more than in IEEE, especially since author names are typically spelled out fully.

For example, if you need to cite a book chapter titled Neuroscience and Behavior by Thomas K. Green from the book Understanding the Human Brain, edited by Janet R. Wilson in 2020, here’s how your citation in Vancouver style would look:

Reference Green TK. Neuroscience and behavior. In: Wilson JR, editor. Understanding the Human Brain. New York: Springer; 2020. p. 143-165.
In-text 1

3. AMA (American Medical Association)

In your medical and scientific writing, you’ll often use the AMA style. It’s a popular choice that uses superscript Arabic numerals for citations in your text, which correspond to full references listed numerically in your reference section.

For example, if you need to cite an article titled Innovations in Cardiology by Emma Rodriguez, published in the American Journal of Cardiology in 2021, your AMA (American Medical Association) style citation would look like this:

Reference Rodriguez E. Innovations in Cardiology. Am J Cardiol. 2021;117(3):456-462.
In-text 1

Here’s an example of how it would look in your text: “In discussing recent advancements, one study highlighted several key innovations in the field of cardiology¹.”

The superscript “¹” refers to the first entry in your reference list, which corresponds to the article by Emma Rodriguez.

4. NLM (National Library of Medicine)

In the fields of medical and scientific research, the NLM citation style is what you’ll often use. It’s structured meticulously to include everything from author names and article titles to journal names, publication years, volume and issue numbers, page ranges, and even the DOI if available.

In-text Johnson MJ, Exercise and Cardiovascular Health. J Cardiovasc Exerc. 2022;10(2):45-56. DOI: 10.1234/jce.2022.012345.
Reference (Johnson, 2020)

With NLM style, you might also add a bit more detail, such as specific article page numbers or the issue number of the journal, making sure that anyone reading your work can easily locate your sources. This style keeps your citations clear and comprehensive, supporting the high standards of documentation required in scientific communities.

5. ACS (American Chemical Society)

When you’re working in chemistry or a similar discipline, ACS style is your go-to for citing sources. This approach uses numerical citations in square brackets within your text. These numbers link directly to a reference list at the end of your document where you’ll provide complete details like the journal name, volume, and page numbers.

For instance, if you need to cite an article titled New Frontiers in Organic Chemistry by Laura Bell, published in the Journal of Chemical Research in 2022, here’s how you’d format it using ACS style:

Reference Bell, L. New Frontiers in Organic Chemistry. J. Chem. Res. 2022, 45 (3), 234-245.
In-text (Bell, 2022)

Note Reference Styles

1. Chicago Notes and Bibliography

In your work, you might find yourself using the Chicago Notes and Bibliography style, especially if you’re writing in history or the arts. This style uses footnotes or endnotes for citations and includes a separate bibliography with full details of your sources.

Bibliography Tyrion, Alistair. Title of the Work. Publisher, 2020.
Footnote 1. Alistair Tyrion, Title of the Work (Publisher, 2020), 45.


Be consistent. Stick to one citation style throughout your paper. Mixing styles can confuse your readers and make your work look messy. Keeping it consistent makes your writing clear and professional.

2. Bluebook (Legal Citations)

In your legal writing, you’ll likely use The Bluebook style. It’s mainly used for legal documents and focuses on citing cases, statutes, law review articles, and other legal materials. These citations typically appear in footnotes or inline, depending on the specific guidelines of the legal document or publication. This makes sure your references are precise and adhere to legal standards.

Footnote Smith v. Jones, 500 U.S. 100 (2021).

3. OSCOLA (Oxford Standard for the Citation of Legal Authorities)

In your legal writing in the UK, you’ll often use the OSCOLA citation style. This style relies on footnotes and a bibliography to cite legal authorities, with specific rules for case names, statutes, and more.

Footnote Miller v Thompson [2020] EWCA Civ 123.

When you’re working on a legal document or an academic paper, your citations will typically appear in footnotes.

Which Citation and Reference Style Should I Use?

I know that finding the perfect citation style for your work can be a bit confusing and even overwhelming, especially with so many options out there to choose from. But don’t you worry, because you’re not alone. Your choice usually depends on your academic institution, instructor, or the nature of your document, whether it’s a research paper, thesis, or article.

When you’re writing a research paper, APA or Chicago citation styles are excellent choices. These styles are perfect for listing many references, making sure everyone knows where your information comes from.

If you’re working on a social sciences report, the APA style is often used with its neat author-date citations, keeping things clear and organized. For a humanities report, the MLA style is a great option. It uses author-page number citations, making it easy to locate specific parts of a work and facilitating textual analysis and discussion. If you’re going into journal articles or research papers in computer science or engineering, the IEEE citation format is ideal. It’s specifically designed for the precision needed in these fields.

When it comes to larger projects like a thesis or dissertation, you’ll need to follow more specific rules. For articles, the citation style you use can vary depending on where you’re publishing or what you’re writing about.

In any case, the best thing to do is to ask your instructor about the citation style you should use. The type of academic paper you are working on, the requirements of your instructor, and the discipline of your work all play a role in choosing the apt citation style for your work. If your instructor doesn’t provide guidance on citation styles, you can do some quick research to find out which style is commonly used in your field of work. For example, medical papers often use the American Medical Association (AMA) style.

If you are a teacher, it would be helpful to let your students know which style of citation you expect them to use and how to put it together correctly. It would save time to check for plagiarism later on if you included examples of the citations.

It’s really important to educate your students about the dishonesty of copying someone else’s work without giving credit and the legal and academic consequences that can come from not citing sources properly. Make sure to clearly differentiate between plagiarism and legitimate citation. Explain how proper citation acknowledges the original creator, upholds academic integrity, and helps avoid the serious costs of plagiarism. This way, your students will understand the weight of giving credit where it’s due and maintaining academic honesty.

Here’s a quick guide to help you choose the correct citation style:

Discipline Typical Citation Style(s)
Humanities MLA, Chicago Notes and Bibliography
Social Sciences APA, ASA
Economics Harvard
Medicine AMA; NLM; Vancouver
Psychology APA
Political science APSA
Sciences ACS, CSE
Law Bluebook, OSCOLA
Engineering & IT IEEE


Citing sources is your way of saying, “I got this idea from here.” Not citing properly can get you in trouble for plagiarism, so be careful.

To cut a long story short, citing your sources is like nailing the final piece of an academic jigsaw. It’s not just about dodging plagiarism. It’s about giving credit where it’s due. Use Guru’s guide as your GPS to make sure your work is both well-written and well-cited.


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