MementoUtils.MEMENTO_RESOURCE + "/";
HashSet<String> links = new HashSet<String>();
//first, last and current are mandatory
if( first == null || last == null || current == null) throw new MementoException("Memento links cannot be produced");
links.add(buildLink(prefix,original.toString(),first.getCommitTime(),"first memento"));
links.add(buildLink(prefix,original.toString(),last.getCommitTime(),"last memento"));
links.add(buildLink(prefix,original.toString(),current.getCommitTime(),"memento"));