diff --git a/simple_singly_linked_list.c b/simple_singly_linked_list.c
index 9e1c4ee..a89ffc9 100644
--- a/simple_singly_linked_list.c
+++ b/simple_singly_linked_list.c
@@ -34,24 +34,203 @@
 #include "simple_singly_linked_list.h"
 
 /** The type of list nodes */
+typedef struct IntListNodeData* IntListNode;
 
 /** The implementation of list node data */
+struct IntListNodeData {
+   int data;
+   IntListNode next;
+};
 
 /** The implementation of list data */
+struct IntListData {
+   IntList list;
+};
 
 
 /* ===================================================================== */
 /* private list functions */
 
 /* abstract away and generalize also memory allocation for list nodes */
-static <node-type> list_obtain_node(<params>) {
+static IntListNode list_obtain_node(int data) {
+   return 0;
 }
 
-static void list_release_node(<node-type>) {
+static void list_release_node(IntListNode node) {
+   return;
 }
 
 /* optional: implement a function for printing the content of the list - may be useful for debugging */
 void list_dump(char* prefix, IntList list) {
+   return;
 }
 
 /* ===================================================================== */
+
+
+/**
+ * Obtains ('creates') and provides a 'new' list instance.
+ * Any list obtained via this function MUST be released using
+ * function `release_list()`.
+ * 
+ * Note: This function does not make any assumptions 
+ * about how list components, esp. nodes, are allocated.
+ * 
+ * @return IntList The list instance or 0, if no list could by instantiated.
+ */
+IntList list_obtain() {
+   return 0;
+}
+
+/**
+ * Releases a list that was obtained earlier via function `obtain_list`.
+ * Released lists MUST NOT be used anymore.
+ * 
+ * Note: The implementation of this function does not make any assumptions
+ * about the allocation method of list elements, but MUST match the implementation
+ * of function `obtain_list` as its inverse function.
+ * 
+ * @param p_list The pointer to the list to release. The value of the pointer
+ * is set to 0, if the list was successfully released, otherwise it is left untouched.
+ */
+void list_release(IntList* p_list) {
+   return;
+}
+
+/**
+ * Determines whether or not the given list is valid.
+ * 
+ * @param list The list to evaluate.
+ * @return `True` if the list is valid, false otherwise.
+ */
+bool list_is_valid(IntList list) {
+   return 0;
+}
+
+/**
+ * Determines whether or not the list contains at least one item.
+ * 
+ * @param list The list to evaluate.
+ * @return `False` if the list contains one or more items, `true` otherwise.
+ */
+bool list_is_empty(IntList list) {
+   return 0;
+}
+
+/**
+ * Provides the number of values stored in the list.
+ * 
+ * @param list The list to evaluate.
+ * @return The number of values the list contains.
+ */
+int list_get_size(IntList list) {
+   return 0;
+}
+
+/**
+ * Determines whether or not the list given list contains the queried value
+ * at least once.
+ * 
+ * @param list The list to query.
+ * @param value The value.
+ * @return `True` if the list contains at least one instance of the value, 
+ * `false ` otherwise.
+ */
+bool list_contains(IntList list, int value) {
+   return 0;
+}
+
+/**
+ * Provides the value stored in the list at the given position.
+ * 
+ * @param list The list from which the value shall be retrieved.
+ * @param index The zero-based position index of the value to retrieve.
+ * @return The value stored at the given position or 0, if the position
+ * is not available.
+ */
+int list_get_at(IntList list, unsigned int index) {
+   return 0;
+}
+
+/**
+ * Inserts the given value at the end of the given list.
+ * 
+ * @param list The list to which the value shall be appended.
+ * @param value The value to append to the list.
+ */
+void list_insert(IntList list, int value) {
+   return;
+}
+
+/**
+ * Inserts the given value at the indexed position in a way the 
+ * the inserted value is on that position. The index is
+ * - similar to arrays - zero-based. If the the list is shorter
+ * than the indexed position, the value is inserted at the end
+ * of the list.
+ * 
+ * @param list The list into which the value shall be appended.
+ * @param index The position index of the value to insert.
+ * @param value  The value to insert.
+ */
+void list_insert_at(IntList list, unsigned int index, int value) {
+   return;
+}
+
+/**
+ * Appends the `list_to_append` at the end of the given `list`.
+ * The appended list is empty afterwards, because all nodes of that list
+ * have been transferred to `list`.
+ * 
+ * @param list The list that receives the other list.
+ * @param list_to_append The list that is appended to `list`.
+ */
+void list_append(IntList list, IntList list_to_append) {
+   return;
+}
+
+/**
+ * Removes the first occurrance of `value` from the given list.
+ * If the list does not contain that value, the list shall not
+ * be modified.
+ * 
+ * @param list The list from which the given value shall be removed.
+ * @param value The value to remove from the list.
+ */
+void list_remove(IntList list, int value) {
+   return;
+}
+
+/**
+ * Removes all occurrances of `value` from the list.
+ * If the list does not contain that value, the list shall not
+ * be modified.
+ * 
+ * @param list The list from which all occurrances of `value` shall be removed.
+ * @param value The `value` to remove throughout the list.
+ */
+void list_remove_all(IntList list, int value) {
+   return;
+}
+
+/**
+ * Removes the value at the indexed position from the given list
+ * and provides that value. If the list does not have a value
+ * at that position, the list remains unmodified.
+ * 
+ * @param list The list from which the value at the given index shall be returned.
+ * @param index The zero-based index of the value to return.
+ * @return The removed value or 0 in case of errors.
+ */
+int list_remove_at(IntList list, unsigned int index) {
+   return 0;
+}
+
+/**
+ * Clears the given list by removing all values from the list.
+ * 
+ * @param list The list to clear.
+ */
+void list_clear(IntList list) {
+   return;
+}
\ No newline at end of file