There are no instructions to let the user know how to use the graph.
At first glance, the graph doesn't look like it is possible to be interacted with. (Instead of the 'move' cursor upon hover, we should use the 'point' cursor. We can also animate the edges by highlighting upon mouse hover to let the user know that it is clickable)
Clicking on the node does nothing but clicking on the node label brings up the list of authors that are adjacent to the node. This is not intuitive. The label is too small to be noticed.