Reference:

Seppo Ovaska, Olli Vainio, and Matti Pöllä. Adaptive filtering using multiplicative general parameters for zero-crossing detection. IEEE Transactions on Industrial Electronics, 50(6):1340–1342, December 2003.

Suggested BibTeX entry:

@article{ovaska03,
    author = {Seppo Ovaska and Olli Vainio and Matti P\"{o}ll\"{a}},
    journal = {IEEE Transactions on Industrial Electronics},
    month = {December},
    number = {6},
    pages = {1340--1342},
    title = {Adaptive filtering using multiplicative general parameters for zero-crossing detection},
    volume = {50},
    year = {2003},
}