1. Astala, K., Faraco, D., Székelyhidi Jr., L.: Convex integration and the L
$$^{p}$$
p
theory of elliptic equations. Ann. Sc. Norm. Super. Pisa Cl. Sci. (5) 7(1), 1–50 (2008)
2. Bressan, A., Flores, F.: On total differential inclusions. Rend. Sem. Mat. Univ. Padova 92, 9–16 (1994)
3. Cellina, A.: A view on differential inclusions. Rend. Semin. Mat. Univ. Politec. Torino 63(3), 197–209 (2005)
4. Córdoba, D., Faraco, D., Gancedo, F.: Lack of uniqueness for weak solutions of the incompressible porous media equation. Arch. Ration. Mech. Anal. 200(3), 725–746 (2011)
5. Chlebik, M., Kirchheim, B.: Rigidity for the four gradient problem. J. Reine Angew. Math. 2002(551), 1–9 (2002)