def phdos_label_from_units(units):
    """
    Return latex string for phonon DOS values in ``units``.
    """
    d = {'ev': '(states/eV)', 'mev': '(states/meV)', 'ha': '(states/Ha)',
        'cm-1': '(states/cm$^{-1}$)', 'cm^-1': '(states/cm$^{-1}$)', 'thz':
        '(states/Thz)'}
    try:
        return d[units.lower().strip()]
    except KeyError:
        raise KeyError(
            'Value for units `{}` unknown\nPossible values are:\n {}'.
            format(units, list(d.keys())))
