@Article{Masso98c,
    author = {J. Mass{\'o} and E. Seidel and Wai-Mo Suen and P. Walker},
    title = {Event Horizons in Numerical Relativity II: Analyzing the Horizon},
    journal = {Phys. Rev. D},
    year = {1999},
    volume = {59},
    pages = {064015}
}