  We survey at the general level, and in a rather wide and historical context,
some less known mathematical details of various mean free path statistics in
nuclear emulsion as applied to relativistic projectile fragmentations. A number
of comments are provided on Feller's paradox, ordered, censored, and truncated
statistics, Erlang and Poisson observers of nuclear emulsion. All these issues
are related to the statistical approaches used about a decade ago at Berkeley
Bevalac for anomalons, some of which should be considered as standard methods
for mean free paths' estimators of relativistic heavy ions.
