@article{do05a,
    author = {Döllner, Jürgen},
    journal = {Journal of Cartography and Geographic Information Science},
    title = {Constraints as Means of Controlling Usage of Geovirtual Environments},
    year = {2005},
    number = {2},
    pages = {69--80},
    volume = {32},
    publisher = {Taylor \& Francis},
    doi = {10.1559/1523040053722132},
}