@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 = {115},
 number = {2},
 month = feb,
 year = {2015},
 pages = {336--342},
}