--- branches/development/src/io/ParamConstraint.hpp	2010/07/09 23:08:25	1465
+++ branches/development/src/io/ParamConstraint.hpp	2013/05/15 15:09:35	1874
@@ -35,8 +35,9 @@
  *                                                                      
  * [1]  Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).             
  * [2]  Fennell & Gezelter, J. Chem. Phys. 124, 234104 (2006).          
- * [3]  Sun, Lin & Gezelter, J. Chem. Phys. 128, 24107 (2008).          
- * [4]  Vardeman & Gezelter, in progress (2009).                        
+ * [3]  Sun, Lin & Gezelter, J. Chem. Phys. 128, 234107 (2008).          
+ * [4]  Kuang & Gezelter,  J. Chem. Phys. 133, 164101 (2010).
+ * [5]  Vardeman, Stocker & Gezelter, J. Chem. Theory Comput. 7, 834 (2011).
  */
  
 #ifndef IO_PARAMCONSTRAINT_HPP
@@ -59,7 +60,7 @@ namespace OpenMD {
   struct NotEmptyConstraint : public ParamConstraintFacade<NotEmptyConstraint>{
     
     NotEmptyConstraint() { description_= "nonempty";}
-    bool operator()( const std::string data ) const {
+    bool operator()( const std::string &data ) const {
       return !data.empty();
     }
   };
@@ -360,7 +361,7 @@ namespace OpenMD {
 
   template<typename T>
   inline LessThanOrEqualToConstraint<T> isLessThanOrEqualTo(T& v ) {
-    return ParamConstraintFacade<LessThanOrEqualToConstraint<T> >(v);
+    return LessThanOrEqualToConstraint<T>(v);
   }
 
   template<typename T>