diff --git a/eo/src/eo b/eo/src/eo
index 3851a06b..f1b91a00 100644
--- a/eo/src/eo
+++ b/eo/src/eo
@@ -57,6 +57,8 @@
 #include <eoOpContainer.h>
 // combinations of simple eoOps (eoMonOp and eoQuadOp)
 #include <eoProportionalCombinedOp.h>
+// didactic (mimics SGA-like variation into an eoGenOp)
+#include <eoSGAGenOp.h>
 
 // population
 #include <eoPop.h>
diff --git a/eo/src/eoSGAGenOp.h b/eo/src/eoSGAGenOp.h
new file mode 100644
index 00000000..262e662b
--- /dev/null
+++ b/eo/src/eoSGAGenOp.h
@@ -0,0 +1,141 @@
+// -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-
+
+//-----------------------------------------------------------------------------
+// eoSGAGenOp.h
+// (c) Marc.Schoenauer 2002
+/*
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+    Contact: todos@geneura.ugr.es, http://geneura.ugr.es
+             Marc.Schoenauer@inria.fr
+             mak@dhi.dk
+ */
+//-----------------------------------------------------------------------------
+
+#ifndef _eoSGAGenOp_h
+#define _eoSGAGenOp_h
+
+#include "eoGenOp.h"
+#include "eoInvalidateOps.h"
+///////////////////////////////////////////////////////////////////////////////
+// class eoSGAGenOp
+///////////////////////////////////////////////////////////////////////////////
+
+/** ***************************************************************************
+ * eoSGAGenOp (for Simple GA) mimicks the usual crossover with proba pCross + 
+ * mutation with proba pMut inside an eoGeneralOp
+ * It does it exactly as class eoSGATransform, i.e. only accepts 
+ *    quadratic crossover and unary mutation
+ * It was introduced for didactic reasons, but seems to be popular :-)
+ *****************************************************************************/
+template<class EOT> 
+class eoSGAGenOp : public eoGenOp<EOT>
+{
+ public:
+    
+  /** Ctor from crossover (with proba) and mutation (with proba)
+   * Builds the sequential op that first applies a proportional choice
+   * between the crossover and nothing (cloning), then the mutation
+   */
+  eoSGAGenOp(eoQuadOp<EOT>& _cross, double _pCross, 
+		 eoMonOp<EOT>& _mut, double _pMut)
+    : cross(_cross),
+      pCross(_pCross),
+      mut(_mut), 
+      pMut(_pMut) 
+  {
+    // the crossover - with probability pCross
+    propOp.add(cross, pCross); // crossover, with proba pcross
+    propOp.add(quadClone, 1-pCross); // nothing, with proba 1-pcross
+    
+    // now the sequential
+    op.add(propOp, 1.0);	 // always do combined crossover
+    op.add(mut, pMut);     // then mutation, with proba pmut
+  }
+  
+  /** do the job: delegate to op */
+  virtual void apply(eoPopulator<EOT>& _pop)
+  {
+    op.apply(_pop);
+  }
+
+  /** inherited from eoGenOp */
+  virtual unsigned max_production(void) {return 2;}
+
+  virtual string className() const {return "eoSGAGenOp";}
+
+
+ private:
+  eoQuadOp<EOT> &cross;   // eoInvalidateXXX take the boolean output
+  double pCross;
+  eoMonOp<EOT> & mut;      // of the XXX op and invalidate the EOT
+  double pMut;
+  eoProportionalOp<EOT> propOp;
+  eoQuadCloneOp<EOT> quadClone;
+  eoSequentialOp<EOT> op;
+};
+
+/** ***************************************************************************
+ * eoASGAGenOp (for Almost Simple GE) mimicks proportional application of 
+ * one crossover and one mutation, together with a clone operator, each one
+ * with relative weights.
+ * This is the other almost-standard application of variation operators 
+ * (see eoSGAGenOp for the completely standard).
+ *****************************************************************************/
+template<class EOT> 
+class eoASGAGenOp : public eoGenOp<EOT>
+{
+ public:
+    
+  /** Ctor from crossover (with proba) and mutation (with proba)
+   * Builds the sequential op that first applies a proportional choice
+   * between the crossover and nothing (cloning), then the mutation
+   */
+  eoASGAGenOp(eoQuadOp<EOT>& _cross, double _pCross, 
+		 eoMonOp<EOT>& _mut, double _pMut, double _pCopy)
+    : cross(_cross),
+      pCross(_pCross),
+      mut(_mut), 
+      pMut(_pMut),
+      pCopy(_pCopy)
+  {
+    op.add(cross, pCross); // crossover, with proba pcross
+    op.add(quadClone, pCopy); // nothing, with proba pCopy
+    op.add(mut, pMut);     // mutation, with proba pmut
+  }
+  
+  /** do the job: delegate to op */
+  virtual void apply(eoPopulator<EOT>& _pop)
+  {
+    op.apply(_pop);
+  }
+
+  /** inherited from eoGenOp */
+  virtual unsigned max_production(void) {return 2;}
+
+  virtual string className() const {return "eoASGAGenOp";}
+
+
+ private:
+  eoQuadOp<EOT> &cross;   // eoInvalidateXXX take the boolean output
+  double pCross;
+  eoMonOp<EOT> & mut;      // of the XXX op and invalidate the EOT
+  double pMut;
+  eoMonCloneOp<EOT> monClone;
+  eoProportionalOp<EOT> op;
+};
+
+
+#endif