@article {baerland2020observation,
	title = {An observation on the uniform preconditioners for the mixed Darcy problem},
	journal = {Numerical Methods for Partial Differential Equations},
	volume = {36},
	number = {6},
	year = {2020},
	pages = {1718{\textendash}1734},
	publisher = { Wiley},
	author = {B{\ae}rland, Trygve and Kuchta, Miroslav and Mardal, Kent-Andre and Thompson, Travis}
}
@article {baerland2019multigrid,
	title = {Multigrid Methods for Discrete Fractional Sobolev Spaces},
	journal = {SIAM Journal on Scientific Computing},
	volume = {41},
	number = {2},
	year = {2019},
	pages = {A948{\textendash}A972},
	publisher = {{SIAM},
	author = {B{\ae}rland, Trygve and Kuchta, Miroslav and Mardal, Kent-Andre}
}
