question: What is the cmi cross reference id that is related to at least one council tax entry? List the cross reference id and source system code.
#1 return cmis cross reference  id 
#2 return council tax entries that #1 related to 
#3 return number of  #2 for each #1 
#4 return #1 where #3 is at least one 
#5 return source system codes of #4 
#6 return #4 ,  #5