KOPAL, J., ROZLOŽNÍK, M., TŮMA, M. Approximate Inverse Preconditioners with Adaptive Dropping. Advances in Engineering Software. 2015, 84(June), 13-20. ISSN 0965-9978. E-ISSN 1873-5339. Available: https://doi.org/10.1016/j.advengsoft.2015.01.006