You can print all authors (or any column that have multiple items) using
Action Chains plugin, by having a pre-defined formula action with the following template:
Code:
program:
category_items('authors')
Attached below is a chain the performs this action, all you have to do is import it into the plugin: Action Chains > Add/Modify chains > right click the table > import.
After importing the chain, you should see a menu entry called "Print all authors". By invoking it; all authors will be printed into a dialog, where you can copy them.