A graph \(G\) is \([a, b]\)-covered if each edge of \(G\) belongs to an \([a, b]\)-factor. Here, a necessary and sufficient condition for a graph to be \([a, b]\)-covered is given, and it is shown that an \([m, n]\)-graph is \([a, b]\)-covered if \(bm – na \geq 2(n-b)\) and \(0 \leq a < b \leq n\).