We will discuss two papers evaluating the notion of "conservative"
Durlofsky, L.J.: “Accuracy of mixed and control volume finite element approximations to Darcy velocity and related quantities,” Water Resources Research, 30, 965-973 (1994).
Thomas J. R. Hughes, Gerald Engel, Luca Mazzei, and Mats G. Larson, The Continuous Galerkin Method
Is Locally Conservative, Journal of Computational Physics 163, 467–488 (2000)