articles:
http://akarnokd.blogspot.com.by/2017/12/java-9-flow-api-multicasting-via.html
http://akarnokd.blogspot.com.by/2017/09/java-9-flow-api-mapping-asynchronously.html
http://akarnokd.blogspot.com.by/2017/09/java-9-flow-api-ordered-merge.html
http://akarnokd.blogspot.com.by/2017/09/java-9-flow-api-switching-threads.html
http://akarnokd.blogspot.com.by/2017/09/java-9-flow-api-timing-out-events.html
http://akarnokd.blogspot.com.by/2017/09/java-9-flow-api-arbitration-and.html
http://akarnokd.blogspot.com.by/2017/09/java-9-flow-api-taking-and-skipping.html

books:
Jog - Reactive Programming with Java 9