You can share references with other people using the Groups function. Any documents associated with a source associated with a group will be viewable and editable by all individuals that have access, which is great if you are working collaboratively on a project.
You can add someone to a group by right clicking on the group and selecting "Manage Group".
The "Preferences" window will then open with an overview of the group. To invite other people to the group, click "Invite Members" and add their email addresses to the designated box. Then click "Send Invites". You can also manage membership to the group at any time in this window.