function sort ( r : list ) : list;
	var	lowf,lowl, midf,midl, highf,highl : list;

	begin
	if r = nil then	begin	Last := nil;	sort := r end
	else	begin
		lowf := nil;	midf := nil;	highf := nil;
		{*** First key becomes splitter ***}
		tailins( r, midf, midl );
		r := r^.next;
		while r<>nil do begin
			if r^.k<midf^.k then	tailins(r,lowf,lowl)
			else if r^.k=midf^.k then	tailins(r,midf,midl)
				else	tailins(r,highf,highl);
			r := r^.next
			end;
		{*** Assemble resulting list ***}
		if lowf <> nil then begin
			lowl^.next := nil;
			sort := sort(lowf);
			Last^.next := midf
			end
		else	sort := midf;
		if highf <> nil then highl^.next := nil;
		midl^.next := sort(highf);
		if Last = nil then Last := midl
		end
	end;