def blaney_criddle(tmean, p, k=0.85):
    """Evaporation calculated according to [blaney_1952]_.

    Parameters
    ----------
    tmean: pandas.Series, optional
        average day temperature [°C]
    p: pandas.Series/float, optional
        bright sunshine (hour day-1)
    k: float, optional
        calibration coefficient [-]

    Returns
    -------
    pandas.Series containing the calculated evaporation.

    Examples
    --------
    >>> et_blaney_criddle = blaney_criddle(tmean)

    Notes
    -----
    Based on equation 6 in [xu_2001]_.

    .. math:: PE=kp(0.46 * T_a + 8.13)

    References
    ----------
    .. [blaney_1952] Blaney, H. F. (1952). Determining water requirements in
       irrigated areas from climatological and irrigation data.
    .. [xu_2001] Xu, C. Y., & Singh, V. P. (2001). Evaluation and
       generalization of temperature‐based methods for calculating evaporation.
       Hydrological processes, 15(2), 305-319.
    """
    et = k * p * (0.46 * tmean + 8.13)
    return et