The nodes are linked to the parent node "Back-Door Criterion" (except for "Controlling for everything is misguided" which is linked to "Why not controll for a descent of x?"). This allows for easier access to concepts when exploring the games that Pearl has created and allows people to easily refer back to concepts discussed in these games.

In the "The Book of Why," Pearl often refers to the past views of confounders when explaining his games and showing why it is not sufficient. This was discussed in great detail in pages 150-156, but it could be difficult to refer to when only looking at the games. 1Cademy has the node "Classical Epidemiological Definition of a Confounder" which provides a simple description that can be more easily located than searching through the book alone.