I use many different applications in my workflow one such application is DEVONThink 3 which stores my papers and media. DEVONThink 3 has a URI scheme allowing you to link to indervidual documents at page level. The scheme in this case is x-devonthink-item produced via “copy item link” or “copy page link.”
examples:
x-devonthink-item://899B16DB-87CB-4233-A33B-B6522E1AAAAC
x-devonthink-item://899B16DB-87CB-4233-A33B-B6522E1AAAAC?page=10
You can even put them in webpages eventhough they only work locally.
Many apps have there own and some have several schemes
my suggestion is if such a scheme is pasted into source or hyperlinks that the OpenURL function would open them as expected by the OS. So for example I can set the source to point to the document and page in DEVONthink which it will open once clicked.
It also might be useful for REMNOTE to have its own so you can link to REMNOTE content from other applications.