Use of a DOI is recommended but not required in MLA citation style. If no DOI is available, you may include a URL for the location of the resource. Recording a DOI as the location of a digital resource is advantageous because it is a permanent identifier, unlike a URL, which may change over time.
Here is an example of an MLA Style reference with DOI:
If the DOI is not preceded by http:// or https:// in your source, precede the DOI in your reference with the following:
https://doi.org/
According to CrossRef, a DOI (digital object identifier) is a "unique alphanumeric string assigned to a digital object, such as an electronic journal, article, report, or thesis. Each DOI name is unique and serves as a stable, persistent link to the full-text of an electronic item on the Internet".
MLA Style encourages you to include a DOI when available for digital resources. If no DOI is assigned and the reference was retrieved online, you may give the URL. Do not include any text before 'www' in the URL, including http://.
If you ONLY have the DOI and need to find article information, use the following link :
From there, you can type or paste the DOI in the search box. The search will (in most cases) lead you to the publisher's website.