Text ( visual ) : unmediated Heeding the call for change : suggestions for curricular action / edited by Lynn Arthur Steen. -- [Washington, D.C.] : Mathematical Association of America , c1992. -- ix, 247 p. ; 28 cm. -- (MAA notes ; no. 22). -- Includes bibliographical references. -- ISBN 0883850796 ; (BA21756439) ; https://ci.nii.ac.jp/ncid/BA21756439 Author Heading(s): Steen, Lynn Arthur