@Article{Libson94a,
    author = {Joseph Libson and Joan Mass{\'o} and Edward Seidel and Wai-Mo Suen and Paul Walker},
    title = {Event horizons in numerical relativity: Methods and tests},
    journal = {Phys. Rev. D},
    year = {1996},
    volume = {53},
    number = {8},
    pages = {4335-4350},
    note = {PHY94-07882,PHY94-04788,ASC93-18152}
}