Is it possible to refer attributes and tables in other document?
Not yet. it is something we have been exploring but it is not implemented yet.
Thanks for the reply Mallika. This feature really would help and I can give you plenty of use cases for it!
Other users would like this too (see this post, Share tables over 2 documents)
If you implemented this solution, it would also temporarily solve another feature request:
- The ability to have more fine tuned permission control. (see Granular Permissions)
This has been a longstanding issue with airtable. It will seriously hold coda back. Implement a central table library and reap the rewards! 
Here’s a workaround that you may use, if you still need it