Where the reference name are created?

[mikeninerbravog]

Howdy!
Where this kind of reference is created (function, path)? For eg.:
"... where he critiques the claims made by Michael Bellesiles regarding firearms history (Clayton2001 pages 300-302). In addition to his historical work, Cramer is also employed as a software engineer, indicating a diverse professional background (Clayton2001 pages 300-302)."

Clayton2001? Is there a way to print the filename instead of this kind of reference? For example

...firearms history (FoobarReport.pdf pages 300-302). In addition ....

Thanks in advance!