1. Apache ZooKeeper’s issue tracking system. https://issues.apache.org/jira/projects/ZOOKEEPER/issues
2. Issue: ZK-2845. https://issues.apache.org/jira/browse/ZOOKEEPER-2845
3. Issue: ZK-3615. https://issues.apache.org/jira/browse/ZOOKEEPER-3615
4. Issue: ZK-3911. https://issues.apache.org/jira/browse/ZOOKEEPER-3911
5. MET. https://github.com/Lingzhi-Ouyang/MET