P307: Enumeration of all maximum independent set of a graph

P307: Enumeration of all maximum independent set of a graph
Input:
A graph $G = (V, E)$ with maximum degree 4.
Output:
All maximum independent set of $G$.
Complexity:
$O(2^{0.228|V|})$ total time and polynomial space.
Comment:
Reference:
[Beigel1999] (Bibtex)