diff --git a/uppsrc/Core/Value.cpp b/uppsrc/Core/Value.cpp
index 840b1a6a1..8afbf6868 100644
--- a/uppsrc/Core/Value.cpp
+++ b/uppsrc/Core/Value.cpp
@@ -651,7 +651,11 @@ Value& Value::GetAdd(const Value& key)
 {
 	if(IsNull())
 		*this = ValueMap();
-	ASSERT(IsRef() && ptr()->GetType() == VALUEMAP_V);
+	if(GetType() == VALUEARRAY_V) {
+		ValueMap m = *this;
+		*this = m;
+	}
+	ASSERT(GetType() == VALUEMAP_V);
 	return ValueMap::Clone((ValueMap::Data*&)ptr()).GetAdd(key);
 }
 
diff --git a/uppsrc/Core/Value.h b/uppsrc/Core/Value.h
index 52aefc46a..ce9d8e2ad 100644
--- a/uppsrc/Core/Value.h
+++ b/uppsrc/Core/Value.h
@@ -255,10 +255,10 @@ public:
 	const Value& operator[](const Id& key) const;
 	
 	Value& At(int i);
+	Value& operator()(int i)              { return At(i); }
 	void   Add(const Value& src);
 	template <typename T>
 	Value& operator<<(const T& src)       { Add(src); return *this; }
-	Value& operator()(int i)              { return At(i); }
 
 	Value& GetAdd(const Value& key);
 	Value& operator()(const String& key);
diff --git a/uppsrc/Core/ValueUtil.h b/uppsrc/Core/ValueUtil.h
index b2bf8b5df..455913080 100644
--- a/uppsrc/Core/ValueUtil.h
+++ b/uppsrc/Core/ValueUtil.h
@@ -373,12 +373,12 @@ public:
 	const Value& operator[](const Id& key) const     { return operator[](Value(key.ToString())); }
 
 	Value& GetAdd(const Value& key);
-	Value& At(int i);
 	Value& operator()(const Value& key)              { return GetAdd(key); }
 	Value& operator()(const String& key)             { return operator()(Value(key)); }
 	Value& operator()(const char *key)               { return operator()(Value(key)); }
 	Value& operator()(const int key)                 { return operator()(Value(key)); }
 	Value& operator()(const Id& key)                 { return operator()(Value(key.ToString())); }
+	Value& At(int i);
 	
 	Value GetAndClear(const Value& key);
 
diff --git a/uppsrc/Core/src.tpp/Value$en-us.tpp b/uppsrc/Core/src.tpp/Value$en-us.tpp
index 4cc446225..262fb5b3d 100644
--- a/uppsrc/Core/src.tpp/Value$en-us.tpp
+++ b/uppsrc/Core/src.tpp/Value$en-us.tpp
@@ -161,6 +161,35 @@ through any contained ValueMaps and ValueArrays too, for other
 Value types it uses the normal operator`=`=.&]
 [s3; &]
 [s4;%- &]
+[s5;:Value`:`:Compare`(const Value`&`)const:%- [@(0.0.255) int]_[* Compare]([@(0.0.255) con
+st]_[_^Value^ Value][@(0.0.255) `&]_[*@3 v])_[@(0.0.255) const]&]
+[s2; Compares value with another value [%-*@3 v]. Types of values must 
+be comparable (e.g. it is possible to compare texts with texts, 
+numbers with numbers etc...). If types are not comparable, returns 
+0. If values are equal, returns 0, `-1 if Value is lesser than 
+[%-*@3 v], 1 if Value if it is greater.&]
+[s3; &]
+[s4;%- &]
+[s5;:Value`:`:operator`<`=`(const Value`&`)const:%- [@(0.0.255) bool]_[* operator<`=]([@(0.0.255) c
+onst]_[_^Value^ Value][@(0.0.255) `&]_[*@3 x])_[@(0.0.255) const]&]
+[s2;%- [%% Same as Compare(][*@3 x]) <`= 0.&]
+[s3; &]
+[s4;%- &]
+[s5;:Value`:`:operator`>`=`(const Value`&`)const:%- [@(0.0.255) bool]_[* operator>`=]([@(0.0.255) c
+onst]_[_^Value^ Value][@(0.0.255) `&]_[*@3 x])_[@(0.0.255) const]&]
+[s2;%- [%% Same as Compare(][*@3 x]) >`= 0.&]
+[s3; &]
+[s4;%- &]
+[s5;:Value`:`:operator`<`(const Value`&`)const:%- [@(0.0.255) bool]_[* operator<]([@(0.0.255) c
+onst]_[_^Value^ Value][@(0.0.255) `&]_[*@3 x])_[@(0.0.255) const]&]
+[s2;%- [%% Same as Compare(][*@3 x]) < 0.&]
+[s3; &]
+[s4;%- &]
+[s5;:Value`:`:operator`>`(const Value`&`)const:%- [@(0.0.255) bool]_[* operator>]([@(0.0.255) c
+onst]_[_^Value^ Value][@(0.0.255) `&]_[*@3 x])_[@(0.0.255) const]&]
+[s2;%- [%% Same as Compare(][*@3 x]) > 0.&]
+[s3; &]
+[s4;%- &]
 [s5;:Value`:`:ToString`(`)const:%- [_^String^ String]_[* ToString]()_[@(0.0.255) const]&]
 [s2; Conversion to text for supporting rich types.&]
 [s3;%- &]
@@ -213,6 +242,64 @@ onst]&]
 [%-*@3 key], returns its value. If not, returns void Value.&]
 [s3;%- &]
 [s4;%- &]
+[s5;:Value`:`:At`(int`):%- [_^Value^ Value][@(0.0.255) `&]_[* At]([@(0.0.255) int]_[*@3 i])&]
+[s2; If Value is Null, sets it to ValueArray. If Value is ValueArray 
+or was Null, returns a reference of element at [%-*@3 i] , if there 
+is none, adds as much Void Values to array as necessarry to have 
+it. If Value is ValueMap, returns a reference to map value at 
+[%-*@3 i] , if there is none, behaviour is undefined (ASSERT in 
+debug mode fails). [^topic`:`/`/Core`/srcdoc`/ValueReference`$en`-us^ The 
+reference returned is invalidated by any further use of originating 
+Value]. If Value is neither ValueArray, Null or ValueMap, behaviour 
+is undefined (ASSERT in debug mode fails).&]
+[s3; &]
+[s4;%- &]
+[s5;:Value`:`:operator`(`)`(int`):%- [_^Value^ Value][@(0.0.255) `&]_[* operator()]([@(0.0.255) i
+nt]_[*@3 i])&]
+[s2; Same as At([%-*@3 i]).&]
+[s3; &]
+[s4;%- &]
+[s5;:Value`:`:Add`(const Value`&`):%- [@(0.0.255) void]_[* Add]([@(0.0.255) const]_[_^Value^ V
+alue][@(0.0.255) `&]_[*@3 src])&]
+[s2; If Value is Null, sets it to ValueArray. If Value is ValueArray 
+or was Null, appends [%-*@3 src] at the end of ArrayValue. If Value 
+is neither ValueArray or Null, behaviour is undefined (ASSERT 
+in debug mode fails).&]
+[s3; &]
+[s4;%- &]
+[s5;:Value`:`:operator`<`<`(const T`&`):%- [@(0.0.255) template]_<[@(0.0.255) typename]_[*@4 T
+]>_[_^Value^ Value][@(0.0.255) `&]_[* operator<<]([@(0.0.255) const]_[*@4 T][@(0.0.255) `&]_[*@3 s
+rc])&]
+[s2; Same as Add([%-*@3 src]).&]
+[s3; &]
+[s4;%- &]
+[s5;:Value`:`:GetAdd`(const Value`&`):%- [_^Value^ Value][@(0.0.255) `&]_[* GetAdd]([@(0.0.255) c
+onst]_[_^Value^ Value][@(0.0.255) `&]_[*@3 key])&]
+[s2; If Value is Null, sets it to ValueMap. If Value is ValueArray, 
+sets it to standard conversion of ValueMap to ValueArray (indicies 
+become keys). If Value is ValueMap or was Null, returns a reference 
+of element at key [%-*@3 key], if there is none, it is created 
+as Void Value. [^topic`:`/`/Core`/srcdoc`/ValueReference`$en`-us^ The 
+reference returned is invalidated by any further use of originating 
+Value]. If Value is neither ValueArray, Null or ValueMap, behaviour 
+is undefined (ASSERT in debug mode fails).&]
+[s3; &]
+[s4;%- &]
+[s5;:Value`:`:operator`(`)`(const String`&`):%- [_^Value^ Value][@(0.0.255) `&]_[* operator
+()]([@(0.0.255) const]_[_^String^ String][@(0.0.255) `&]_[*@3 key])&]
+[s2; Same as GetAdd([%-*@3 key]).&]
+[s3; &]
+[s4;%- &]
+[s5;:Value`:`:operator`(`)`(const char`*`):%- [_^Value^ Value][@(0.0.255) `&]_[* operator()
+]([@(0.0.255) const]_[@(0.0.255) char]_`*[*@3 key])&]
+[s2; Save as GetAdd([%-*@3 key]).&]
+[s3; &]
+[s4;%- &]
+[s5;:Value`:`:operator`(`)`(const Id`&`):%- [_^Value^ Value][@(0.0.255) `&]_[* operator()](
+[@(0.0.255) const]_[_^Id^ Id][@(0.0.255) `&]_[*@3 key])&]
+[s2; Save as GetAdd([%-*@3 key]).&]
+[s3; &]
+[s4;%- &]
 [s5;:Value`:`:operator`=`(const Value`&`):%- [_^Value^ Value][@(0.0.255) `&]_[* operator`=](
 [@(0.0.255) const]_[_^Value^ Value][@(0.0.255) `&]_[*@3 v])&]
 [s2; Assignment.&]
@@ -222,7 +309,6 @@ onst]&]
 [*@3 v])&]
 [s2; Copy constructor.&]
 [s3; &]
-[s3; &]
 [s4;%- &]
 [s5;:Value`:`:Value`(`):%- [* Value]()&]
 [s2; Default constructor, creates void Value.&]
@@ -290,6 +376,17 @@ onst]_[*@4 T][@(0.0.255) `&])_[@(0.0.255) const]&]
 [s2; Conversion to text. ValueType returns empty String.&]
 [s3;%- &]
 [s4;%- &]
+[s5;:ValueType`:`:Compare`(const T`&`)const:%- [@(0.0.255) int]_[* Compare]([@(0.0.255) con
+st]_[*@4 T][@(0.0.255) `&])_[@(0.0.255) const]&]
+[s2; Comparison with another value of the same type. Returns should 
+return `-1, 0, 1.&]
+[s3;%- &]
+[s4;%- &]
+[s5;:ValueType`:`:PolyCompare`(const Value`&`)const:%- [@(0.0.255) int]_[* PolyCompare]([@(0.0.255) c
+onst]_[_^Value^ Value][@(0.0.255) `&])_[@(0.0.255) const]&]
+[s2; Polymorphic comparison with different type.&]
+[s3;%- &]
+[s4;%- &]
 [s5;:ValueType`:`:operator Ref`(`):%- [* operator_Ref]()&]
 [s2; Returns a Ref (generic reference) to the instance of T.&]
 [s0;%- &]
diff --git a/uppsrc/Core/src.tpp/ValueArray$en-us.tpp b/uppsrc/Core/src.tpp/ValueArray$en-us.tpp
index 54ef5426e..bf37cf66f 100644
--- a/uppsrc/Core/src.tpp/ValueArray$en-us.tpp
+++ b/uppsrc/Core/src.tpp/ValueArray$en-us.tpp
@@ -172,6 +172,13 @@ onst]_[_^ValueArray^ ValueArray][@(0.0.255) `&]_[*@3 va])&]
 [s2;%% Returns element at [%-*@3 i].&]
 [s3;%% &]
 [s4; &]
+[s5;:ValueArray`:`:At`(int`): [_^Value^ Value][@(0.0.255) `&]_[* At]([@(0.0.255) int]_[*@3 i])&]
+[s2;%% Returns a reference of element at [%-*@3 i] , if there is none, 
+adds as much Void Values to array as necessarry to have it. [^topic`:`/`/Core`/srcdoc`/ValueReference`$en`-us^ T
+he reference returned is invalidated by any further use of originating 
+Value]. &]
+[s3;%% &]
+[s4; &]
 [s5;:ValueArray`:`:GetHashValue`(`)const: [@(0.0.255) unsigned]_[* GetHashValue]()_[@(0.0.255) c
 onst]&]
 [s2;%% Returns hashing value.&]
diff --git a/uppsrc/Core/src.tpp/ValueMap$en-us.tpp b/uppsrc/Core/src.tpp/ValueMap$en-us.tpp
index 620997381..0c47cc4c1 100644
--- a/uppsrc/Core/src.tpp/ValueMap$en-us.tpp
+++ b/uppsrc/Core/src.tpp/ValueMap$en-us.tpp
@@ -258,6 +258,33 @@ multiple overloads are required to make Id and SqlId work with
 ValueMap.&]
 [s3; &]
 [s4;%- &]
+[s5;:ValueMap`:`:GetAdd`(const Value`&`):%- [_^Value^ Value][@(0.0.255) `&]_[* GetAdd]([@(0.0.255) c
+onst]_[_^Value^ Value][@(0.0.255) `&]_[*@3 key])&]
+[s2; Returns a reference of element at key [%-*@3 key], if there is 
+none, it is created as Void Value. [^topic`:`/`/Core`/srcdoc`/ValueReference`$en`-us^ T
+he reference returned is invalidated by any further use of originating 
+Value].&]
+[s3; &]
+[s4;%- &]
+[s5;:ValueMap`:`:operator`(`)`(const Value`&`):%- [_^Value^ Value][@(0.0.255) `&]_[* operat
+or()]([@(0.0.255) const]_[_^Value^ Value][@(0.0.255) `&]_[*@3 key])&]
+[s5;:ValueMap`:`:operator`(`)`(const String`&`):%- [_^Value^ Value][@(0.0.255) `&]_[* opera
+tor()]([@(0.0.255) const]_[_^String^ String][@(0.0.255) `&]_[*@3 key])&]
+[s5;:ValueMap`:`:operator`(`)`(const char`*`):%- [_^Value^ Value][@(0.0.255) `&]_[* operato
+r()]([@(0.0.255) const]_[@(0.0.255) char]_`*[*@3 key])&]
+[s5;:ValueMap`:`:operator`(`)`(const int`):%- [_^Value^ Value][@(0.0.255) `&]_[* operator()
+]([@(0.0.255) const]_[@(0.0.255) int]_[*@3 key])&]
+[s5;:ValueMap`:`:operator`(`)`(const Id`&`):%- [_^Value^ Value][@(0.0.255) `&]_[* operator(
+)]([@(0.0.255) const]_[_^Id^ Id][@(0.0.255) `&]_[*@3 key])&]
+[s2; Same as GetAdd([%-*@3 key]).&]
+[s3; &]
+[s4;%- &]
+[s5;:ValueMap`:`:At`(int`):%- [_^Value^ Value][@(0.0.255) `&]_[* At]([@(0.0.255) int]_[*@3 i])&]
+[s2; Returns a reference of value at index [%-*@3 i]. [^topic`:`/`/Core`/srcdoc`/ValueReference`$en`-us^ T
+he reference returned is invalidated by any further use of originating 
+Value].&]
+[s3; &]
+[s4;%- &]
 [s5;:ValueMap`:`:GetAndClear`(const Value`&`):%- [_^Value^ Value]_[* GetAndClear]([@(0.0.255) c
 onst]_[_^Value^ Value][@(0.0.255) `&]_[*@3 key])&]
 [s2; If [%-*@3 key] is not present, returns ErrorValue (which is Void 
diff --git a/uppsrc/Core/srcdoc.tpp/ValueReference$en-us.tpp b/uppsrc/Core/srcdoc.tpp/ValueReference$en-us.tpp
new file mode 100644
index 000000000..e3b7d3d1d
--- /dev/null
+++ b/uppsrc/Core/srcdoc.tpp/ValueReference$en-us.tpp
@@ -0,0 +1,45 @@
+topic "Rules for references to Value internal maps elements";
+[2 $$0,0#00000000000000000000000000000000:Default]
+[i448;a25;kKO9;2 $$1,0#37138531426314131252341829483380:class]
+[l288;2 $$2,2#27521748481378242620020725143825:desc]
+[0 $$3,0#96390100711032703541132217272105:end]
+[H6;0 $$4,0#05600065144404261032431302351956:begin]
+[i448;a25;kKO9;2 $$5,0#37138531426314131252341829483370:item]
+[l288;a4;*@5;1 $$6,6#70004532496200323422659154056402:requirement]
+[l288;i1121;b17;O9;~~~.1408;2 $$7,0#10431211400427159095818037425705:param]
+[i448;b42;O9;2 $$8,8#61672508125594000341940100500538:tparam]
+[b42;2 $$9,9#13035079074754324216151401829390:normal]
+[a83;*R6 $$10,12#31310162474203024125188417583966:caption]
+[b83;*2 $$11,12#07864147445237544204411237157677:title]
+[b42;a42;2 $$12,12#45413000475342174754091244180557:text]
+[{_}%EN-US 
+[s10; Rules for references to Value internal maps elements&]
+[s0; Value is originally designed as nonmutable concrete Value of 
+different concrete types.&]
+[s0; &]
+[s0; However, as Value is commonly used to store complex hierarchies 
+(using ValueArray/ValueMap types), it is in the end very useful 
+to be able to reference ValueArray/ValueMap elements directly. 
+Validity of such references is restricted by following rule:&]
+[s0; &]
+[s0; Reference obtained from Value (by Value`::At, Value`::GetAdd, 
+ValueArray`::At, ValueMap`::GetAdd and derivative methods) are 
+[* only valid until the next operation on originating Value `- 
+including just reading it.]&]
+[s0; &]
+[s0; Examples of invalid code:&]
+[s0; &]
+[s0; [*C@5 Value m;]&]
+[s0; [*C@5 Value`& x `= m(`"key`");]&]
+[s0; [*C@5 x `= m; // using m as source invalidates x]&]
+[s0;*C@5 &]
+[s0; [*C@5 Value m;]&]
+[s0; [*C@5 Value`& x `= m(`"key`");]&]
+[s0; [*C@5 Value`& y `= m(`"key2`"); // Invalidates x]&]
+[s0; [*C@5 x `= 123; // undefined]&]
+[s0;*C@5 &]
+[s0; [*C@5 Value m;]&]
+[s0; [*C@5 Value`& x `= m.At(1);]&]
+[s0; [*C@5 Value m2 `= m; // Invalidates x]&]
+[s0; [*C@5 x `= `"fail`"; // undefined]&]
+[s0; ]]
\ No newline at end of file