@Book{OL17355098M,
    title: {Pendulum power},
    author: {Greg Nielsen},
    publisher: {Aquarian},
    year: {1986},
    place: {Wellingborough},
}

@Book{OL7539051M,
    title: {Pendulum Power},
    author: {Greg  and Joseph Polansky Nielsen},
    publisher: {Warner Books},
    year: {1977},
}

@Book{OL8280512M,
    title: {The Pendulum Book},
    author: {Jack F. Chandu},
    publisher: {C.W. Daniel Company, Limited},
    year: {2004},
}

@Author{OL1112193A,
    name: {Jack F. Chandu},
}