diff --git a/JsonPreprocessor/JsonPreprocessor.pdf b/JsonPreprocessor/JsonPreprocessor.pdf
index d14e5a3a..d348298c 100644
Binary files a/JsonPreprocessor/JsonPreprocessor.pdf and b/JsonPreprocessor/JsonPreprocessor.pdf differ
diff --git a/packagedoc/additional_docs/The JSONP format.tex b/packagedoc/additional_docs/The JSONP format.tex
index b92ccb1d..af89857d 100644
--- a/packagedoc/additional_docs/The JSONP format.tex	
+++ b/packagedoc/additional_docs/The JSONP format.tex	
@@ -1191,5 +1191,75 @@ \section{Implicite creation of dictionaries}
 {'paramA': 'ABC', 'subKey': 'ABC', 'testdict': {'subKey': {'subKey': {'paramA': 'DEF'}}}}
 \end{pythonlog}
 
+\vspace{2ex}
+
+\textbf{Reference to existing keys}
+
+It is possible to use parameters to refer to \textit{already existing} keys.
+
+\begin{pythoncode}
+{
+   // <data structure created implicitly>
+   ${testdict.subKey_1.subKey_2.subKey_3} : "ABC",
+
+   // <string parameter with name of an existing key>
+   "keyName_3" : "subKey_3",
+
+   // <parameter used to refer to an existing key>
+   ${testdict.subKey_1.subKey_2.${keyName_3}} : "XYZ"
+}
+\end{pythoncode}
+
+\vspace{2ex}
+
+\textbf{Outcome:}
+
+\begin{pythonlog}
+{'keyName_3': 'subKey_3',
+ 'testdict': {'subKey_1': {'subKey_2': {'subKey_3': 'XYZ'}}}}
+\end{pythonlog}
+
+\vspace{2ex}
+
+Parameters cannot be used to create new keys.
+
+\begin{pythoncode}
+{
+   // <data structure created implicitly>
+   ${testdict.subKey_1.subKey_2.subKey_3} : "ABC",
+
+   // <string parameter with name of a not existing key>
+   "keyName_4" : "subKey_4",
+
+   // <usage of keyName\_4 is not possible here>
+   ${testdict.subKey_1.subKey_2.subKey_3.${keyName_4}} : "XYZ"
+}
+\end{pythoncode}
+
+\vspace{2ex}
+
+\textbf{Outcome is the following error:}
+
+\begin{pythonlog}
+"The implicit creation of data structures based on nested parameter is not supported ..."
+\end{pythonlog}
+
+The same error will happen in case of the standard notation is used:
+
+\begin{pythoncode}
+{
+   // <usage of keyName\_4 is not possible here>
+   ${testdict}['subKey_1']['subKey_2']['subKey_3'][${keyName_4}] : "XYZ"
+}
+\end{pythoncode}
+
+
+
+
+
+
+
+
+
 % --------------------------------------------------------------------------------------------------------------
 
diff --git a/test/testfiles/jpp-test_config_1002.jsonp b/test/testfiles/jpp-test_config_1002.jsonp
index fe94987c..079052fb 100644
--- a/test/testfiles/jpp-test_config_1002.jsonp
+++ b/test/testfiles/jpp-test_config_1002.jsonp
@@ -31,10 +31,11 @@
    "paramD" : "D",
    "paramE" : "E",
    ${testdict_3.paramD.paramE.paramD} : {"E" : 5},
-   ${testdict_3.paramD.paramE.paramD}[${paramE}] : {"F" : 6} // if not implicit, usage of parameters for key names is allowed
    //
-   // needs to be clarified (currently throws an implicit creation error)
-   // ${testdict_4} : {},
-   // ${testdict_4}[${paramD}] : {"G" : 7}
+   // usage of parameters allowed only in case of a key with this name already exists
+
+
+
+   ${testdict_3.paramD.paramE.paramD}[${paramE}] : {"F" : 6} // ${paramE} is accepted because the value is "E" and a key with this name already exists
 }
 
diff --git a/test/testfiles/jpp-test_config_1051.jsonp b/test/testfiles/jpp-test_config_1051.jsonp
index 1d63e26b..766b2245 100644
--- a/test/testfiles/jpp-test_config_1051.jsonp
+++ b/test/testfiles/jpp-test_config_1051.jsonp
@@ -15,7 +15,7 @@
 
 {
    "testdict" : {"A" : 1},
-   "name" : "C",
+   "name"     : "C",
    ${testdict.B.${name}} : 2
 }
 
diff --git a/test/testfiles/jpp-test_config_1052.jsonp b/test/testfiles/jpp-test_config_1052.jsonp
index 4028d7da..90940d10 100644
--- a/test/testfiles/jpp-test_config_1052.jsonp
+++ b/test/testfiles/jpp-test_config_1052.jsonp
@@ -15,7 +15,7 @@
 
 {
    "testdict" : {"A" : 1},
-   "name" : "C",
+   "name"     : "C",
    ${testdict}['${name}']['${name}'] : 2
 }
 
diff --git a/test/testfiles/jpp-test_config_1053.jsonp b/test/testfiles/jpp-test_config_1053.jsonp
index 29b69f56..3e0620ea 100644
--- a/test/testfiles/jpp-test_config_1053.jsonp
+++ b/test/testfiles/jpp-test_config_1053.jsonp
@@ -14,7 +14,7 @@
 //**************************************************************************
 
 {
-   "name" : "C",
+   "name"      : "C",
    "testdict2" : {"B" : 2},
    ${somethingnotexisting.${testdict2}}['${name}'] : 4
 }
diff --git a/test/testfiles/jpp-test_config_1054.jsonp b/test/testfiles/jpp-test_config_1054.jsonp
index 60fcd02e..5faab86a 100644
--- a/test/testfiles/jpp-test_config_1054.jsonp
+++ b/test/testfiles/jpp-test_config_1054.jsonp
@@ -14,7 +14,7 @@
 //**************************************************************************
 
 {
-   "name" : "C",
+   "name"     : "C",
    "testdict" : {"B" : 2},
    ${testdict.${testdict}}['${name}'] : 4
 }
diff --git a/test/testfiles/jpp-test_config_1055.jsonp b/test/testfiles/jpp-test_config_1055.jsonp
index 4bd33f3b..7ec80248 100644
--- a/test/testfiles/jpp-test_config_1055.jsonp
+++ b/test/testfiles/jpp-test_config_1055.jsonp
@@ -14,7 +14,7 @@
 //**************************************************************************
 
 {
-   "name" : "C",
+   "name"     : "C",
    "testlist" : ["B", 2],
    ${testlist.${testlist}}['${name}'] : 4
 }
diff --git a/test/testfiles/jpp-test_config_1056.jsonp b/test/testfiles/jpp-test_config_1056.jsonp
index f96893a0..1dbab24c 100644
--- a/test/testfiles/jpp-test_config_1056.jsonp
+++ b/test/testfiles/jpp-test_config_1056.jsonp
@@ -15,7 +15,7 @@
 
 {
    "testdict" : {"A" : 1},
-   "name" : "C",
+   "name"     : "C",
    ${testdict.${name}}['${name}'] : 5
 }
 
diff --git a/test/testfiles/jpp-test_config_1057.jsonp b/test/testfiles/jpp-test_config_1057.jsonp
index 00f03ef0..9027cd19 100644
--- a/test/testfiles/jpp-test_config_1057.jsonp
+++ b/test/testfiles/jpp-test_config_1057.jsonp
@@ -15,7 +15,7 @@
 
 {
    "testdict" : {"A" : 1},
-   "name" : "C",
+   "name"     : "C",
    ${testdict}[${name}][${name}] : 4
 }
 
diff --git a/test/testfiles/jpp-test_config_1058.jsonp b/test/testfiles/jpp-test_config_1058.jsonp
index 49e1a75e..41c6db28 100644
--- a/test/testfiles/jpp-test_config_1058.jsonp
+++ b/test/testfiles/jpp-test_config_1058.jsonp
@@ -12,6 +12,7 @@
 //  See the License for the specific language governing permissions and
 //  limitations under the License.
 //**************************************************************************
+
 {
    "testdict" : {"A" : 1},
    "name"     : "C",