  In this paper, we prove that relation-extensions of quasi-tilted algebras are
2-Calabi-Yau tilted. With the objective of describing the module category of a
cluster-tilted algebra of euclidean type, we define the notion of reflection so
that any two local slices can be reached one from the other by a sequence of
reflections and coreflections. We then give an algorithmic procedure for
constructing the tubes of a cluster-tilted algebra of euclidean type. Our main
result characterizes quasi-tilted algebras whose relation-extensions are
cluster-tilted of euclidean type.
