def _fill_journal(r, entry):
    """
    Make a "journal" dict
    :param r: BibJSON record dict that will be filled
    :param entry: bibtexparser entry that will be used to fill the BibJSON record
    :return None
    """
    if 'journal' not in entry.keys():
        return
    r['journal'] = {'name': entry['journal']}
    opt_keys = 'number', 'pages', 'month', 'volume'
    for k in opt_keys:
        if k in entry:
            r['journal'][k] = entry[k]
