@unpublished{KoppitzMusunthia2012,
  author  = {J{\"o}rg Koppitz and Tiwadee Musunthia},
  title   = {Maximal subsemigroups containing a particular semigroup},
  institution = {Institut f{\"u}r Mathematik},
  series    = {Preprints des Instituts f{\"u}r Mathematik der Universit{\"a}t Potsdam},
  number    = {1 (2012) 8},
  year    = {2012},
}