Many of the papers citing Stallings paper *A topological proof of Grushko's theorem on free products* are using the binding tie argument.  The ones I found are the following.

 1. Heil [1972] *On Kneser’s conjecture for bounded 3-manifolds*
 2. Feustel [1972] *A splitting theorem for closed orientable 3-manifolds*
 3. Bowditch [1999] *Connectedness properties of limit sets*
 4. Bellettini, Paolini, Wang [2021] *A complete invariant for closed surfaces in the three-sphere*