[1] Bickel P. J.-Lehmann E. L.: Descriptive statistics for nonparameterics models. [a] Introduction. AMS 1975, No. 5, 1044-1048. [b] Dispersion. AMS 1975, No. 5, 1049 to 1068. [c] Spread. Will be published in Hajek's Memorial volume. (1975)
[2] Hájek J.:
A course in nonparametrics statistics. Holden day. San Francisco. (1969)
MR 0246467