@misc{srk2011,
    author = "S{\l}awomir P. Szklarz and Marielba Rojas and Ma{\}gorzata P. Kaleta",
    title = "{The optimization problem in model-reduced gradient-based history matching}",
    note = "Technical Report 11-17, Delft Institute of Applied Mathematics, Delft University of Technology, Delft, The Netherlands, December 2011"
}