private void parenthesisContentsToString(List sentences, StringBuffer sb, String catSym)	{
		for (int i = 0; i < sentences.size(); i++)	{
			Object o = sentences.get(i);
			
			if (o instanceof List)	{
				parenthesisContentsToString((List)o, sb, "");	// catenize symbol only on first level
			}
			else	{
				if (o instanceof String)
					o = SymbolToName.makeIdentifier((String)o, "");	// no "_" for quotes
				sb.append(o.toString());	// ArtificialRule goes here
			}

			if (i < sentences.size() - 1)
				sb.append((catSym.length() > 0 ? "_" + catSym : "") + "_");
		}
	}