Creating a "scrapbook" node type using an entity reference field

I'm building a site that includes two node types, "scrapbook" and "press clipping". A user can create multiple notebooks which are either public or private, and they can also add press clippings to a public pool.

Each notebook includes an entity reference field that allows multiple press clippings to be referenced from each notebook. This works fine, but the only way I can add a reference from a notebook to a press clipping is by editing the notebook. I want to include a dropdown on each press clipping that allows the user to select one of the notebooks they have created and add the press clipping to that notebook.

What's the best way to achieve this result?