@MISC{MIDSP_1.MIZ,
  AUTHOR = {Muzalewski, Micha{\l}},
  TITLE = {Midpoint algebras},
  DAY = {26},
  MONTH = {November},
  YEAR = {1989},
  ADDRESS1 = {Warsaw University\\Bia{\l}ystok},
  SUMMARY = {In this article basic properties of midpoint algebras
are proved. We define a congruence relation $\equiv$ on bound vectors
and free vectors as the equivalence classes of $\equiv$.}}

