R.I.274 APPROXIMATE CONTROLLABILITY OF THE SEMILINEAR HEAT EQUATION C.Fabre J.P.Puel E.Zuazua The whole paper is available as a compressed Postscript file by internet procedure FTP anonymous on host barbes.polytechnique.fr ( 129.104.4.100) in the directory pub/RI/1993 under the name cfabre_al.274.jan.93.ps.gz