Romanowska, Anna B
Modal theory : an algebraic approach to order, geometry, and convexity / A.B. Romanowska, J.D.H. Smith. -- Berlin : Heldermann, 1985. -- xii, 158 s. -- (Research and exposition in mathematics ; vol. 9). -- ISBN : 3-88538-209-1 (brož.).
Smith, Jonathan D. H
algebra. univerzální algebra. algebraické struktury. učebnice
512. 512.5. (075)