is a digital object identifier, a unique, permanent identification number that will take you straight to a document no matter where it is located on the Internet
figures prominently in the APA 7th edition referencing style, and where a book, journal, report or other publication has a DOI, it must be included in the reference
must always be presented in the format https://doi.org/xxxxxx, for e.g. https://doi.org/10.7748/phc.2016.e1162.
the format http://doi.org/xxxxxx (rather than https) is also acceptable to use. However, if the item you are referencing has a DOI in a format other than these, it will need to be changed to the above format
check if the DOI link works correctly before submitting