Anders Björner, Christophe Reutenauer. Rationality of the Möbius Function of Subword Order. Theoretical Computer Science, 98(1):53-63, 1992.
@article{BjornerR92, title = {Rationality of the Möbius Function of Subword Order}, author = {Anders Björner and Christophe Reutenauer}, year = {1992}, researchr = {https://researchr.org/publication/BjornerR92}, cites = {0}, citedby = {0}, journal = {Theoretical Computer Science}, volume = {98}, number = {1}, pages = {53-63}, }