@article{CPRT86, <br>AUTHOR = {Chung, F. R. K.  and Paul, W.J. and Reischuk, R. and Tarjan, R.},<br>TITLE = {Coding Strings by Pairs of Strings},<br>VOLUME = {6(3)}, <br>YEAR = {1986},<br>PAGES = {445--461}, <br>BOOKTITLE = {SIAM Journal on Algorithmic and Discrete Methods}, <br>EE = {http://www.math.ucsd.edu/~fan/mypaps/fanpap/73csbpos_b.PDF},<br>}