@article{cohen-katzir-yehezkel14,
 author =  "Reuven Cohen, Liran Katzir and Aviv Yehezkel",
 title = "A unified scheme for generalizing cardinality estimators to sum aggregation",
 journal =  "Information Processing Letters", 
 volume = ,
 number = ,
 pages = "",
 month = ,
 year  = 
}