WSiP
... that the Polish publishing house WSiP had a monopoly on textbook publishing from the 1950s to 1989?
... that the Polish publishing house <b id="mwBek"><a href="./Wydawnictwa_Szkolne_i_Pedagogiczne" id="mwBeo" rel="mw:WikiLink" title="Wydawnictwa Szkolne i Pedagogiczne">WSiP</a></b> had a monopoly on textbook publishing from the 1950s to 1989?