diff --git a/benchmark/k2_trees/README.md b/benchmark/k2_trees/README.md
index 9168c39f1..84bcab112 100644
--- a/benchmark/k2_trees/README.md
+++ b/benchmark/k2_trees/README.md
@@ -8,9 +8,25 @@ Explored dimensions:
   * test cases
   * methods (`adj`, `neighbors`, `reverse_neighbors`)
 
+## Data
+
+  * The data input for the benchmarking are arc files. An arc file is a text
+      file where each line represents a directed edge between two nodes, the
+      first column is the origin node and the second the target node.
+
+### Test cases
+
+  * EXAMPLE test case uses an small file with a little more than 100 nodes and
+      roughly the same number of edges from web data commons.
+  * HOSTGRAPH is a test case where the data comes from the Web Cropus released
+      by the Common Crawl Foundation in April 2014. The file aggregates the
+      page graph by subdomain/host. It has 123.660.351 edges.
+
 ## Directory structure
 
   * [bin](./bin): Contains the executables of the project.
+    * `build_*` generates the binary file with the graph from the arc files.
+    * `gen_*` executes the experiments.
   * [results](./results): Contains the results of the experiments.
   * [src](./src):  Contains the source code of the benchmark.
   * [visualize](./visualize): Contains a `R`-script which generates
diff --git a/benchmark/k2_trees/k2tree.config b/benchmark/k2_trees/k2tree.config
index 093544127..f15b3cb83 100644
--- a/benchmark/k2_trees/k2tree.config
+++ b/benchmark/k2_trees/k2tree.config
@@ -5,14 +5,14 @@
 # * SDSL_TYPE    : Corresponding sdsl type.
 # * K2_LATEX_NAME: LaTeX name for output in the benchmark report. No underscores are allowed here.
 
-# Different Shapes and Bit-Vectors (Byte-Alphabet):
+# Different k and Bit-Vectors:
 K2_BV;k2_tree<2, bit_vector, bit_vector::rank_1_type>;K2BV
-K3_BV;k2_tree<3, bit_vector, bit_vector::rank_1_type>;K3BV
-K4_BV;k2_tree<4, bit_vector, bit_vector::rank_1_type>;K4BV
-K2_RRR63V;k2_tree<2, rrr_vector<63>, rrr_vector<63>::rank_1_type>;K2RRR63V
+# K3_BV;k2_tree<3, bit_vector, bit_vector::rank_1_type>;K3BV
+# K4_BV;k2_tree<4, bit_vector, bit_vector::rank_1_type>;K4BV
+# K2_RRR63V;k2_tree<2, rrr_vector<63>, rrr_vector<63>::rank_1_type>;K2RRR63V
 # K3_RRR63V;k2_tree<3, rrr_vector<63>, rrr_vector<63>::rank_1_type>;K3RRR63V
 # K4_RRR63V;k2_tree<4, rrr_vector<63>, rrr_vector<63>::rank_1_type>;K4RRR63V
-K2_RRR126V;k2_tree<2, rrr_vector<126>, rrr_vector<126>::rank_1_type>;K2RRR126V
+# K2_RRR126V;k2_tree<2, rrr_vector<126>, rrr_vector<126>::rank_1_type>;K2RRR126V
 # K3_RRR126V;k2_tree<3, rrr_vector<126>, rrr_vector<126>::rank_1_type>;K3RRR126V
 # K4_RRR126V;k2_tree<4, rrr_vector<126>, rrr_vector<126>::rank_1_type>;K4RRR126V
 K2_ILV;k2_tree<2, bit_vector_il<512>, bit_vector_il<512>::rank_1_type>;K2ILV