def latexify(labels, default_latex_labels=None):
    """
    Return a LaTeX-ified label.

    :param labels:
        The label(s) to latexify. 

    :type labels:
        str or iterable of str objects

    :param default_latex_labels: [optional]
        Dictionary of default labels to use.

    :type default_latex_labels:
        dict

    :returns:
        LaTeX-ified label.

    :rtype:
        str or iterable of str objects
    """
    common_labels = {'teff': '$T_{\\rm eff}$ [K]', 'feh': '[Fe/H]', 'logg':
        '$\\log{g}$', 'alpha': '[$\\alpha$/Fe]'}
    if default_latex_labels is not None:
        common_labels.update(default_latex_labels)
    listify = True
    if isinstance(labels, str):
        listify = False
        labels = [labels]
    latex_labels = []
    for label in labels:
        if label in common_labels.keys():
            latex_labels.append(common_labels[label])
        elif label.startswith('f.'):
            aperture = label.split('.')[1]
            latex_labels.append('$ln(f_{{{0}}})$'.format(aperture))
        elif label.startswith('v.'):
            aperture = label.split('.')[1]
            latex_labels.append('$V_{{rad,{{{0}}}}}$ [km/s]'.format(aperture))
        elif label.startswith('z.'):
            aperture = label.split('.')[1]
            latex_labels.append('$z_{{{0}}}$'.format(aperture))
        elif label.startswith('convolve.'):
            aperture = label.split('.')[1]
            latex_labels.append('$\\sigma_{{{0}}}$ [$\\AA$]'.format(aperture))
        elif label.startswith('normalise.'):
            aperture, coefficient = label.split('.')[1:]
            latex_labels.append('${0}_{{{1}}}$'.format(aperture[0],
                coefficient))
        else:
            latex_labels.append(label)
    if not listify:
        return latex_labels[0]
    return latex_labels
