We just need to break this down. Look at what we have. Four names. Four numbers. Four titles or subjects and two directions. We just need to smash them together and figure out how some or all of them are connected.
And thanks to @Robert we know we’re not dealing with the Dewey Decimal System.
And we also know it’s the 42nd Street Library.
EDIT: And yes, I know that me getting directly involved is not orthodox, etc. but I’ll be damned if they’re going to beat us when we’re twelve hours from the finish line.