diff --git a/src/main/java/printer/ExpressionPrinter.java b/src/main/java/printer/ExpressionPrinter.java
index 2ed5997..38e9c41 100644
--- a/src/main/java/printer/ExpressionPrinter.java
+++ b/src/main/java/printer/ExpressionPrinter.java
@@ -1,15 +1,24 @@
+/*!! Printer */
+
+/*!
+ExpressionPrinter
+=================
+
+The `ExpressionPrinter` is used for string serialization of a given `Expression`.
+*/
+
+/*!- Header */
 package printer;
 
 import expression.*;
 import interpreter.Visitor;
 
+/*!
+The `ExpressionPrinter` implements the string serialization with the help of the
+[Visitor](${basePath}/src/main/java/interpreter/Visitor.java.html).
+*/
 public class ExpressionPrinter extends Visitor<String> {
-    private final String value;
-
-    public ExpressionPrinter(Expression expression) {
-        value = visit(expression);
-    }
-
+    /*!- Visit functions */
     public String visitAddition(Addition addition) {
         return visit(addition.leftHandSide) + " + " + visit(addition.rightHandSide);
     }
@@ -26,7 +35,11 @@ public class ExpressionPrinter extends Visitor<String> {
         return visit(subtraction.leftHandSide) + " - " + visit(subtraction.rightHandSide);
     }
 
-    public String getValue() {
-        return value;
+    /*!
+    The `getValue` function takes an `Expression` instance as an argument and returns
+    the string serialisation of the given expression.
+    */
+    public String getValue(Expression expression) {
+        return visit(expression);
     }
 }
diff --git a/src/main/java/printer/ProgramPrinter.java b/src/main/java/printer/ProgramPrinter.java
index 32bf00b..d8529e4 100644
--- a/src/main/java/printer/ProgramPrinter.java
+++ b/src/main/java/printer/ProgramPrinter.java
@@ -1,19 +1,27 @@
+/*!! Printer */
+
+/*!
+ProgramPrinter
+==============
+
+The `ProgramPrinter` is used for string serialization of a given `Program`.
+*/
+
+/*!- Header */
 package printer;
 
 import interpreter.Visitor;
 import program.*;
 
+/*!
+The `ProgramPrinter` implements the string serialization with the help of the
+[Visitor](${basePath}/src/main/java/interpreter/Visitor.java.html).
+*/
 public class ProgramPrinter extends Visitor<String> {
-    private final String value;
-
-    public ProgramPrinter(Program program) {
-        value = visit(program);
-    }
-
+    /*!- Visit functions */
     public String visitAssignment(Assignment assignment) {
-        ExpressionPrinter identifierPrinter = new ExpressionPrinter(assignment.identifier);
-        ExpressionPrinter expressionPrinter = new ExpressionPrinter(assignment.expression);
-        return identifierPrinter.getValue() + " := " + expressionPrinter.getValue();
+        ExpressionPrinter printer = new ExpressionPrinter();
+        return printer.getValue(assignment.identifier) + " := " + printer.getValue(assignment.expression);
     }
 
     public String visitComposition(Composition composition) {
@@ -21,16 +29,20 @@ public class ProgramPrinter extends Visitor<String> {
     }
 
     public String visitConditional(Conditional conditional) {
-        ExpressionPrinter conditionPrinter = new ExpressionPrinter(conditional.condition);
-        return "if (" + conditionPrinter.getValue() + ") then { " + visit(conditional.thenCase) +  " } else { " + visit(conditional.elseCase) + " }";
+        ExpressionPrinter printer = new ExpressionPrinter();
+        return "if (" + printer.getValue(conditional.condition) + ") then { " + visit(conditional.thenCase) +  " } else { " + visit(conditional.elseCase) + " }";
     }
 
     public String visitLoop(Loop loop) {
-        ExpressionPrinter conditionPrinter = new ExpressionPrinter(loop.condition);
-        return "while (" + conditionPrinter.getValue() + ") { " + visit(loop.program) +  " }";
+        ExpressionPrinter printer = new ExpressionPrinter();
+        return "while (" + printer.getValue(loop.condition) + ") { " + visit(loop.program) +  " }";
     }
 
-    public String getValue() {
-        return value;
+    /*!
+    The `getValue` function takes a `Program` instance as an argument and returns
+    the string serialisation of the given program.
+    */
+    public String getValue(Program program) {
+        return visit(program);
     }
 }
diff --git a/src/test/java/printer/ExpressionPrinterTest.java b/src/test/java/printer/ExpressionPrinterTest.java
index a639995..d4bfa2d 100644
--- a/src/test/java/printer/ExpressionPrinterTest.java
+++ b/src/test/java/printer/ExpressionPrinterTest.java
@@ -5,9 +5,6 @@ import org.junit.Test;
 
 import static org.junit.Assert.*;
 
-/**
- * Created by nils on 15.01.2017.
- */
 public class ExpressionPrinterTest {
     final String identifierCode = "a";
     final Identifier identifier = new Identifier(identifierCode);
@@ -24,26 +21,26 @@ public class ExpressionPrinterTest {
 
     @Test
     public void testVisitAddition() {
-        ExpressionPrinter printer = new ExpressionPrinter(addition);
-        assertEquals(additionCode, printer.getValue());
+        ExpressionPrinter printer = new ExpressionPrinter();
+        assertEquals(additionCode, printer.getValue(addition));
     }
 
     @Test
     public void testVisitIdentifier() {
-        ExpressionPrinter printer = new ExpressionPrinter(identifier);
-        assertEquals(identifierCode, printer.getValue());
+        ExpressionPrinter printer = new ExpressionPrinter();
+        assertEquals(identifierCode, printer.getValue(identifier));
     }
 
     @Test
     public void testVisitInt() {
-        ExpressionPrinter printer = new ExpressionPrinter(integer);
-        assertEquals(integerCode, printer.getValue());
+        ExpressionPrinter printer = new ExpressionPrinter();
+        assertEquals(integerCode, printer.getValue(integer));
     }
 
     @Test
     public void testVisitSubtraction() {
-        ExpressionPrinter printer = new ExpressionPrinter(subtraction);
-        assertEquals(subtractionCode, printer.getValue());
+        ExpressionPrinter printer = new ExpressionPrinter();
+        assertEquals(subtractionCode, printer.getValue(subtraction));
     }
 
 }
\ No newline at end of file
diff --git a/src/test/java/printer/ProgramPrinterTest.java b/src/test/java/printer/ProgramPrinterTest.java
index 9a3c4c9..107f5e2 100644
--- a/src/test/java/printer/ProgramPrinterTest.java
+++ b/src/test/java/printer/ProgramPrinterTest.java
@@ -27,32 +27,32 @@ public class ProgramPrinterTest {
 
     @Test
     public void testVisitAssignment() {
-        ProgramPrinter printer = new ProgramPrinter(assignment);
-        assertEquals(assignmentCode, printer.getValue());
+        ProgramPrinter printer = new ProgramPrinter();
+        assertEquals(assignmentCode, printer.getValue(assignment));
     }
 
     @Test
     public void testVisitComposition() {
-        ProgramPrinter printer = new ProgramPrinter(composition);
-        assertEquals(compositionCode, printer.getValue());
+        ProgramPrinter printer = new ProgramPrinter();
+        assertEquals(compositionCode, printer.getValue(composition));
     }
 
     @Test
     public void testVisitConditional() {
-        ProgramPrinter printer = new ProgramPrinter(conditional);
-        assertEquals(conditionalCode, printer.getValue());
+        ProgramPrinter printer = new ProgramPrinter();
+        assertEquals(conditionalCode, printer.getValue(conditional));
     }
 
     @Test
     public void testVisitLoop() {
-        ProgramPrinter printer = new ProgramPrinter(loop);
-        assertEquals(loopCode, printer.getValue());
+        ProgramPrinter printer = new ProgramPrinter();
+        assertEquals(loopCode, printer.getValue(loop));
     }
 
     @Test
     public void testVisitProgram() {
-        ProgramPrinter printer = new ProgramPrinter(program);
-        assertEquals(programCode, printer.getValue());
+        ProgramPrinter printer = new ProgramPrinter();
+        assertEquals(programCode, printer.getValue(program));
     }
 
 }
\ No newline at end of file