On monoids, $$2$$ 2 -firs, and semifirs
Crossref DOI link: https://doi.org/10.1007/s00233-014-9586-z
Published Online: 2014-04-23
Published Print: 2014-10
Update policy: https://doi.org/10.1007/springer_crossmark_policy
Bergman, George M.
Text and Data Mining valid from 2014-04-23