On the Stability of Pressure and Velocity Computations for Heterogeneous Reservoirs. - Are Magnus Bruaset; Bjørn Fredrik Nielsen (SIAM J. Appl. Math., 1996)

On the Approximation of the Solution of the Pressure Equation by Changing the Domain. - Aslak Tveito; Bjørn Fredrik Nielsen (SIAM J. Appl. Math., 1997)

Computing the size and location of myocardial ischemia using measurements of ST-segment shift. - Mary C. MacLachlan; Bjørn Fredrik Nielsen; Ola Marius Lysaker; Aslak Tveito (IEEE Trans. Biomed. Eng., 2006)

Optimal monodomain approximations of the bidomain equations. - Bjørn Fredrik Nielsen; Tomas Syrstad Ruud; Glenn Terje Lines; Aslak Tveito (Appl. Math. Comput., 2007)

On the use of the resting potential and level set methods for identifying ischemic heart disease: An inverse problem. - Bjørn Fredrik Nielsen; Marius Lysaker; Aslak Tveito (J. Comput. Phys., 2007)

A note on the efficiency of the conjugate gradient method for a class of time-dependent problems. - Xing Cai; Bjørn Fredrik Nielsen; Aslak Tveito (Numer. Linear Algebra Appl., 2007)

An order optimal solver for the discretized bidomain equations. - Kent-André Mardal; Bjørn Fredrik Nielsen; Xing Cai; Aslak Tveito (Numer. Linear Algebra Appl., 2007)

A Computationally Efficient Method for Determining the Size and Location of Myocardial Ischemia. - Tomas Syrstad Ruud; Bjørn Fredrik Nielsen; Ola Marius Lysaker; Joakim Sundnes (IEEE Trans. Biomed. Eng., 2009)

Can ECG Recordings and Mathematics tell the Condition of Your Heart? - Bjørn Fredrik Nielsen; Marius Lysaker; Per Grøttum; Kent-André Mardal; Aslak Tveito; Christian Tarrou; Kristina Hermann Haugaa; Andreas Abildgaard; Jan Gunnar Fjeld (Simula Research Laboratory, 2010)

Efficient Preconditioners for Optimality Systems Arising in Connection with Inverse Problems. - Bjørn Fredrik Nielsen; Kent-André Mardal (SIAM J. Control. Optim., 2010)

Observability of Ischemia and the Need for Patient Specific Geometrical Models in Inverse ECG. - Glenn T. Lines; Marius Lysaker; Bjørn Fredrik Nielsen (CinC, 2013)

Computing Ischemic Regions in the Heart: On the Use of Internal Electrodes. - Ola Marius Lysaker; Bjørn Fredrik Nielsen; Samuel T. Wall (CinC, 2013)

Analysis of the Minimal Residual Method Applied to Ill Posed Optimality Systems. - Bjørn Fredrik Nielsen; Kent-André Mardal (SIAM J. Sci. Comput., 2013)

Computing Ischemic Regions in the Heart With the Bidomain Model - First Steps Towards Validation. - Bjørn Fredrik Nielsen; Ola Marius Lysaker; Per Grottum (IEEE Trans. Medical Imaging, 2013)

Bidomain Simulations of Subendocardial Ischemia: The Forward and Inverse Problems. - Marius Lysaker; Bjørn Fredrik Nielsen; Samuel T. Wall (CinC, 2014)

The split Bregman algorithm applied to PDE-constrained optimization problems with total variation regularization. - Ole Løseth Elvetun; Bjørn Fredrik Nielsen (Comput. Optim. Appl., 2016)

PDE-Constrained Optimization with Local Control and Boundary Observations: Robust Preconditioners. - Ole Løseth Elvetun; Bjørn Fredrik Nielsen (SIAM J. Sci. Comput., 2016)

Laplacian Preconditioning of Elliptic PDEs: Localization of the Eigenvalues of the Discretized Operator. - Tomás Gergelits; Kent-André Mardal; Bjørn Fredrik Nielsen; Zdenek Strakos (SIAM J. Numer. Anal., 2019)

Sparsity regularization for inverse problems with nullspaces. - Ole Løseth Elvetun; Bjørn Fredrik Nielsen (CoRR, 2020)

Generalized Spectrum of Second Order Differential Operators. - Tomás Gergelits; Bjørn Fredrik Nielsen; Zdenek Strakos (SIAM J. Numer. Anal., 2020)

Numerical approximation of the spectrum of self-adjoint continuously invertible operators. - Tomás Gergelits; Bjørn Fredrik Nielsen; Zdenek Strakos (CoRR, 2021)

Box constraints and weighted sparsity regularization for identifying sources in elliptic PDEs. - Ole Løseth Elvetun; Bjørn Fredrik Nielsen (CoRR, 2022)

Numerical approximation of the spectrum of self-adjoint operators in operator preconditioning. - Tomás Gergelits; Bjørn Fredrik Nielsen; Zdenek Strakos (Numer. Algorithms, 2022)

Fictitious null spaces for improving the solution of injective inverse problems. - Ole Løseth Elvetun; Kim Knudsen; Bjørn Fredrik Nielsen (CoRR, 2024)

A Simple Formula for the Generalized Spectrum of Second Order Self-Adjoint Differential Operators. - Bjørn Fredrik Nielsen; Zdenek Strakos (SIAM Rev., 2024)

Weighting operators for sparsity regularization. - Ole Løseth Elvetun; Bjørn Fredrik Nielsen; Niranjana Sudheer (CoRR, 2025)