Before revision:  We propose a linear delay and polynomial space ] ]  algorithm for enumerating all minimal Steiner trees of (G, W), which improves a previously known polynomial delay enumeration algorithm in [Kimelfeld and Sagiv, Inf.
After revision:  We propose a linear delay and polynomial space ] ] pointed out the problem of enumerating K-fragments is of great importance in a keyword search on data graphs. In a graph-theoretic term, the problem corresponds to enumerating minimal Steiner trees in (directed) graphs. In this paper, we propose a linear-delay and polynomial-space algorithm for enumerating all minimal Steiner trees of (G, W), which improves a previously known polynomial delay enumeration algorithm in [Kimelfeld and Sagiv, Inf.