“…The analysis and implementation of such methods have drawn most of the attention of researchers interested in modern least-squares finite element methods and there exists an abundant mathematical and engineering literature devoted to this subject; see, e.g., [3], [9], [11]- [19], [25], [34], [36], [47], [54], [57], [50], [51], [53], [59], [68], [87], [90]- [94], [96], [99], [105], [112], and [117] among others. As a result, least-squares finite element methods in these settings are among the best understood, studied, and tested from both the theoretical and computational viewpoints.…”