Chunmei Liu Yinglei Song Legand L. Burge III Parameterized lower bound and inapproximability of polylogarithmic string barcoding. 39-49 2008 16 J. Comb. Optim. 1 http://dx.doi.org/10.1007/s10878-007-9097-x db/journals/jco/jco16.html#LiuSB08