  A rapidly expanding fireball which undergoes first-order phase transition
will supercool and proceed via spinodal decomposition. Hadrons are produced
from the individual fragments as well as the left-over matter filling the space
between them. Emission from fragments should be visible in rapidity
correlations, particularly of protons. In addition to that, even within narrow
centrality classes, rapidity distributions will be fluctuating from one event
to another in case of fragmentation. This can be identified with the help of
Kolmogorov-Smirnov test. Finally, we present a method which allows to sort
events with varying rapidity distributions in such a way, that events with
similar rapidity histograms are grouped together.
