Index: generic/include/adt/btree.h
===================================================================
--- generic/include/adt/btree.h	(revision ff75d3461d47855390b19a32cc04d25d47a28c74)
+++ generic/include/adt/btree.h	(revision 296cc1b00a0b0d407da1b7afbe1dca5d4402d8b8)
@@ -34,5 +34,5 @@
 #include <adt/list.h>
 
-#define BTREE_M		4
+#define BTREE_M		5
 #define BTREE_MAX_KEYS	(BTREE_M - 1)
 
@@ -53,6 +53,6 @@
 	/**
 	 * Pointers to descendants of this node sorted according to the key array.
-	 * subtree[0] points to subtree with keys lesser than or equal to key[0].
-	 * subtree[1] points to subtree with keys greater than key[0] and lesser than or equal to key[1].
+	 * subtree[0] points to subtree with keys lesser than to key[0].
+	 * subtree[1] points to subtree with keys greater than or equal to key[0] and lesser than key[1].
 	 * ...
 	 * There is room for storing a subtree pointer for the extra key.
@@ -81,5 +81,5 @@
 
 extern void btree_insert(btree_t *t, __native key, void *value, btree_node_t *leaf_node);
-extern void btree_remove(btree_t *t, __native key);
+extern void btree_remove(btree_t *t, __native key, btree_node_t *leaf_node);
 extern void *btree_search(btree_t *t, __native key, btree_node_t **leaf_node);
 
Index: generic/src/adt/btree.c
===================================================================
--- generic/src/adt/btree.c	(revision ff75d3461d47855390b19a32cc04d25d47a28c74)
+++ generic/src/adt/btree.c	(revision 296cc1b00a0b0d407da1b7afbe1dca5d4402d8b8)
@@ -29,5 +29,5 @@
 /*
  * This B-tree has the following properties:
- * - it is a ballanced 2-3-4 tree (i.e. BTREE_M = 4)
+ * - it is a ballanced 2-3-4-5 tree (i.e. BTREE_M = 5)
  * - values (i.e. pointers to values) are stored only in leaves
  * - leaves are linked in a list
@@ -61,4 +61,6 @@
 #define INDEX_NODE(n)		((n)->subtree[0] != NULL)
 #define LEAF_NODE(n)		((n)->subtree[0] == NULL)
+
+#define FILL_FACTOR		((BTREE_M-1)/2)
 
 #define MEDIAN_LOW_INDEX(n)	(((n)->keys-1)/2)
@@ -172,7 +174,23 @@
 }
 
-/* TODO */
-void btree_remove(btree_t *t, __native key)
-{
+/** Remove B-tree node.
+ *
+ * @param B-tree.
+ * @param key Key to be removed from the B-tree along with its associated value.
+ * @param leaf_node If not NULL, pointer to the leaf node where the key is found.
+ */
+void btree_remove(btree_t *t, __native key, btree_node_t *leaf_node)
+{
+	btree_node_t *lnode;
+	
+	lnode = leaf_node;
+	if (!lnode) {
+		if (!btree_search(t, key, &lnode)) {
+			panic("B-tree %P does not contain key %d\n", t, key);
+		}
+	}
+	
+	/* TODO */
+
 }