(DAML-S) Concurrent, Split, and Unordered, any difference?

I've been trying to search for daml-s examples using  ControlConstruct 
such as Concurrent, Split, etc., but in vain.    The documents available 
on DAML-S official website seems to give very abstract and confusing 
specifications of those ControlConstructs.  I am particularly interested 
to know what's the difference among Concurrent, Split, and Unordered.   If 
Concurrent and Unordered only differs in the execution order (One requires 
concurrently and the other doesn't care.), then what is different for 
Split? 

I would really appreciate it if anyone can give me some clarifications or 
solid examples using those constructs. 

Many thanks,
Sisi