If going for oracle, take a look at dbfs and Secure Files.
Secure Files says it all, keep ALL your data safe in the database. It is organized in lobs. Secure Files is a modernized version of lobs, that should be activated.
dbfs is a filesystem in the database. You can mount it similar like a network filesystem, on a Linux host. It is real powerful. See blog It also has a lot of options to tune to your specific needs. Being a dba, given a filesystem (based in the database, mounted on Linux), I created an Oracle Database on it without any problems. (a database, stored in a ... database). Not that this would be very useful but it does show the power.
More advantages are: availability, backup, recovery, all read consistent with the other relational data.
A reference in a table to something outside the database is unsafe. It can be manipulated, is hard to check and can easily get lost. How about transactions? The database offers solutions for all these issues. With Oracle DBFS you can give your docs to non database applications and they wouldn't even know they are poking in a database.