Exact observability, square functions and spectral theory - Bernhard Hermann Haak; El-Maati Ouhabaz (CoRR, 2011)

Invariance of convex sets for non-autonomous evolution equations governed by forms. - Wolfgang Arendt; Dominik Dier; El-Maati Ouhabaz (J. Lond. Math. Soc., 2014)

Controllability and observability for non-autonomous evolution equations: The averaged Hautus test. - Bernhard H. Haak; Duc-Trung Hoang; El-Maati Ouhabaz (Syst. Control. Lett., 2019)