public void indexLine(String line) {
	if (line.length() > 0) {
	    System.err.println ("Check  for link reff: " + line);
	    // check for up to 3 spaces?
	    if (line.charAt(0) == '[') {
		StringBuilder linkId = new StringBuilder();
		StringBuilder urn = new StringBuilder();
		StringBuilder caption = new StringBuilder();
		// read until ']'
		int idx = Utils.readUntil(linkId, line, 1, ']') ;
		System.err.println("Found linkId: " + linkId);
		idx++;
		if (line.charAt(idx) == ':') {
		    idx++;
		    while ((line.charAt(idx) == ' ') && (idx < line.length())) {
			idx++;
		    }
		    idx = Utils.readUntil(urn,line,idx,' ','\n');
		}
		// consume space, with quote:
		while ((line.charAt(idx) == ' ') || (line.charAt(idx) == '"') || (line.charAt(idx) == '\n')) {
		    idx++;
		}
		idx = Utils.readUntil(caption,line,idx,'"','\n');

		System.err.println ("Linkid: " + linkId + ", urn " + urn + ", caption " + caption);

		final LinkRef lr = new LinkRef(urn.toString(), caption.toString(), false);
		this.addLinkRef(linkId.toString(), lr);
	    }
	}
    }