plane stress, steady-state, mode I asymptotic solution for elastic / perfectly plastic materials

I would like to inform the fracture mechanics community of an asymptotic solution for the steady-state mode I crack problem for an elastic / perfectly plastic material under plane stress loading conditons.  See the following article in ZAMP, i.e., 

Unger, D.J. Plane stress asymptotic solution for steady crack growth in an elastic/perfectly plastic solid for mode I crack propagation. Z. Angew. Math. Phys. 74, 77 (2023). https://link.springer.com/article/10.1007/s00033-022-01916-4