Writing an English professional thesis involves meticulous attention to detail, particularly in the formatting and citation of references. Properly citing sources is crucial for academic integrity and to acknowledge the contributions of others. Below are examples of how to format references in APA, MLA, and Chicago styles, which are commonly used in various academic disciplines.

### APA Style Example

APA style is widely used in social sciences. Here is an example of how to cite a journal article:

**Journal Article:**

Smith, J., & Doe, A. (2020). The impact of technology on education. *Journal of Educational Technology*, 45(3), 214-230. https://doi.org/10.1080/15391523.2020.1796456

**Book:**

Johnson, L., & Williams, M. (2018). *Understanding Research Methods*. Routledge.

**Website:**

World Health Organization. (2021). Global health estimates. Retrieved from https://www.who.int/data/gho

### MLA Style Example

MLA style is commonly used in humanities and literature. Here is an example of how to cite a book:

**Book:**

Doe, John. *The Art of Writing*. Oxford University Press, 2019.

**Journal Article:**

Smith, Jane, and Alice Doe. "The Impact of Technology on Education." *Journal of Educational Technology*, vol. 45, no. 3, 2020, pp. 214-30.

**Website:**

World Health Organization. "Global Health Estimates." World Health Organization, 2021, www.who.int/data/gho.

### Chicago Style Example

Chicago style is often used in history and business fields. Here are examples for different types of sources:

**Book:**

Doe, John Q., ed. *Modern Management Practices*. University Press, 2018.

**Article in a Journal:**

Smith, Jane E., and Alice W., "Technology's Role in Education," *Educational Review*, vol. 78, no. 3 (May 2019): 45-67.

**Website:**

World Health Organization website. "Global Health Estimates." Last modified October 2021, https://www.who.int/data/gho.

When writing an English professional thesis