diff --git a/include/common.h b/include/common.h
index d62e9dc..5d9b4b3 100644
--- a/include/common.h
+++ b/include/common.h
@@ -189,6 +189,7 @@ private:
  const int8_t* Blob(size_t* size) const override {*size=sizeof(T); return reinterpret_cast<const int8_t*>(&val);}
 
 public:
+ ObjectSimple() = delete;
  ObjectSimple(T t):val(t) {}
  ObjectSimple(const T* t):val(*t) {}
  ~ObjectSimple() {}
@@ -215,7 +216,6 @@ public:
 
  // Own functions
  T Value() const {return val;}
- void SetValue(T s) {val=s;}
 };
 
 // Simple objects
@@ -238,21 +238,15 @@ private:
  std::string name;
  std::shared_ptr<const ObjectBase> val;
 
+ ObjectPair(const ObjectPair* p):name(p->name),val(p->val) {}
 public:
- ObjectPair() {}
- ObjectPair(const std::string& n, const ObjectBase* v):name(n) {val.reset(v);}
- ObjectPair(const std::string* n, const ObjectBase* v):name(*n) {val.reset(v);}
- ~ObjectPair() {}
+ ObjectPair() = delete;
+ ObjectPair(const std::string& n, const ObjectBase* v):name(n),val(v) {}
+ ObjectPair(const std::string* n, const ObjectBase* v):name(*n),val(v) {}
  // Pure virtual overrides
- const ObjectBase* Copy() const override
- {
-  auto ret=new ObjectPair;
-  ret->name=name; ret->val=val;
-  return ret;
- }
+ const ObjectBase* Copy() const override {return new ObjectPair(this);}
  bool Print() const override
  {
-  if(!Exist()) return false;
   COUT(NORMAL)<<std::endl<<"Object type: "<<Type()<<std::endl;
   COUT(NORMAL)<<"Name is: "<<Name()<<std::endl;
   COUT(NORMAL)<<"Value type: "<<val->Type()<<std::endl;
@@ -264,20 +258,18 @@ public:
  std::string Dump() const override { return Name()+"="+val->Dump(); }
 
  // Own functions
- bool Exist() const {return nullptr!=val.get();}
  const ObjectBase* Get(const std::string& gname) const
  {
   if(gname==name) return val->Copy();
   else return new ObjectError("ObjectPair Get","pair has name "+name+" not "+gname);
  }
- // This function is same as Get but return pointer on constant object
+ // This function is same as Get but return pointer on non-copied object (this pointer must not be deleted)
  const ObjectBase* Find(const std::string& gname) const
  {
   if(gname==name) return val.get();
   else return nullptr;
  }
  std::string Name() const {return name;}
- void SetPair(const std::string& n, const ObjectBase* v) {if(!Exist()) {name=n; val.reset(v);}}
  const ObjectBase* Value() const {return val.get();}
 };
 
@@ -289,20 +281,14 @@ public:
 private:
  std::shared_ptr<ListValues> vals;
 
+ ObjectList(const ObjectList* o):vals(o->vals) {}
 public:
  ObjectList() {vals.reset(new ListValues, [](ListValues* p){for(auto& i: *p) delete i; delete p;});}
  ObjectList(const ObjectBase* o) {vals.reset(new ListValues, [](ListValues* p){for(auto& i: *p) delete i; delete p;}); PushBack(o);}
- ~ObjectList() {}
  // Pure virtual overrides
- const ObjectBase* Copy() const override
- {
-  auto ret=new ObjectList;
-  ret->vals=vals;
-  return ret;
- }
+ const ObjectBase* Copy() const override {return new ObjectList(this);}
  bool Print() const override
  {
-  if(!Exist()) return false;
   COUT(NORMAL)<<std::endl<<"Object type: "<<Type()<<std::endl;
   COUT(NORMAL)<<"Number of elements: "<<Size()<<std::endl;
   return true;
@@ -320,17 +306,16 @@ public:
 
  // Own functions
  const ObjectBase* At(ListValues::size_type i) const {return (*vals)[i];}
- bool Exist() const {return 0!=vals->size();}
  const ObjectBase* Get(const std::string& gname) const
  {
   const ObjectBase* p=Find(gname);
   return (nullptr==p)?new ObjectError("ObjectList Get","name "+gname+" not found in list"):p->Copy();
  }
- // This function is same as Get but return pointer on constant object
+ // This function is same as Get but return pointer on non-copied object (this pointer must not be deleted)
  const ObjectBase* Find(const std::string& gname) const
  {
   const ObjectBase* p;
-  for(auto& i: *vals)
+  for(const auto& i: *vals)
   {
    p=nullptr;
    OBType<ObjectPair> pair(i);