@article{Kristiansen_2004,
    doi = {10.1016/j.tcs.2003.10.016},
    url = {https://doi.org/10.1016%2Fj.tcs.2003.10.016},
    year = {2004},
    month = {jun},
    publisher = {Elsevier {BV}},
    volume = {318},
    number = {1-2},
    pages = {139--161},
    author = {L. Kristiansen and K.-H. Niggl},
    title = {On the computational complexity of imperative programming languages},
    journal = {Theoretical Computer Science}
}

@article{Kristiansen_2004, doi = {10.1016/j.tcs.2003.10.016}, url = {https://doi.org/10.1016%2Fj.tcs.2003.10.016}, year = {2004}, month = {jun}, publisher = {Elsevier {BV}}, volume = {318}, number = {1-2}, pages = {139--161}, author = {L. Kristiansen and K.-H. Niggl}, title = {On the computational complexity of imperative programming languages}, journal = {Theoretical Computer Science} }