Jansen, Thomas (1998), "Introduction to the Theory of Complexity and Approximation Algorithms", in Mayr, Ernst W.; Prömel, Hans Jürgen; Steger, Angelika (eds.), Lectures on Proof Verification and Approximation Algorithms, Lecture Notes in Computer Science, vol. 1367, Springer, pp. 5–28, doi:10.1007/BFb0053011, ISBN9783540642015. See discussion following Definition 1.30 on p. 20.
doi.org
Jansen, Thomas (1998), "Introduction to the Theory of Complexity and Approximation Algorithms", in Mayr, Ernst W.; Prömel, Hans Jürgen; Steger, Angelika (eds.), Lectures on Proof Verification and Approximation Algorithms, Lecture Notes in Computer Science, vol. 1367, Springer, pp. 5–28, doi:10.1007/BFb0053011, ISBN9783540642015. See discussion following Definition 1.30 on p. 20.
