“…It is well known that a second order accurate approximation to the solution of an interface problem can be generated by the Galerkin finite element method with the standard linear basis functions if the triangulation is aligned with the interface, that is, a body fitted mesh is used (see, e.g., Babuška, 1970;Bramble and King, 1996;Chen and Zou, 1998;Xu, 1982;Karczewska and Boguniewicz, 2016 (Anitescu, 2017), or DPG, a discontinuous Petrov-Galerkin finite element method (Carstensen and Weggler, 2014).…”