I am trying to reconstruct this paper:
F. Zobiri, E. Witrant, and F. Bonne, “PDE Observer Design for Counter-Current Heat Flows in a Heat-Exchanger,” IFAC-PapersOnLine, vol. 50, no. 1, pp. 7127–7132, 2017.
https://doi.org/10.1016/j.ifacol.2017.08.548
Not yet completed, but coming soon (hopefully :-) )