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Statistics in theory and practice
Connor, Lewis Roussez, (1977)
The data game : controversies in social science statistics
Maier, Mark, (1991)
Obšta teorija na statistikata i ikonomičeska
Gatev, Kiril I., (1989)
An introduction to index numbers
Morrell, A. J. H., (1948)
Labour turnover
Morrell, A. J. H., (1955)
Tests of corespondence between statistical grouping and formulae
Bowley, Arthur Lyon, (1923)