A reference or reference link is a direct link to a specific resource on a specific site. It also has an editable field to describe the resource.
Below is an example of a reference. It was created by opening a Factory, then dragging a Page Flag on top of it.
An automatic chalkboard eraser is an example of technology that creates efficiency without impacting learning.
Clicking on the Flag will bring you to the resource on the specified site. Clicking on the link works like clicking on a normal link, and preferences local versions.