Split pubnote into journal information.

def split_pubnote(pubnote_str):
    """Split pubnote into journal information."""
    pubnote = {}
    parts = pubnote_str.split(',')

    if len(parts) > 2:
        pubnote['journal_title'] = parts[0]
        pubnote['journal_volume'] = parts[1]
        pubnote['page_start'], pubnote['page_end'], pubnote['artid'] = split_page_artid(parts[2])

    return {key: val for (key, val) in six.iteritems(pubnote) if val is not None}