Topological Ordering of a List of
Randomly-Numbered Elements of a Network
A network of directed line segments free of circular
elements is assumed.  The lines are identified 
by their terminal nodes and the nodes are assumed to
be numbered by a non-topological system.  Given 
a list of these lines in numeric order, a simple technique
can be used to create at high speed a list 
in topological order.
CACM April, 1961
Lasser, D. J.
