diff --git a/exercises/ex04_solution/heised.ipynb b/exercises/ex04_solution/heised.ipynb
index 2e201362b215fd7f1d17e991b60e3e66634a348e..4f94aa75dc5d72bd7e37c0b6f70019f6dfc90f64 100644
--- a/exercises/ex04_solution/heised.ipynb
+++ b/exercises/ex04_solution/heised.ipynb
@@ -6,7 +6,7 @@
    "source": [
     "### Exact Diagonalization\n",
     "\n",
-    "A C++ code for exact diagonalization is attached to this solution sheet, and can be compiled by following the instructions provided with the skeleton code. Numeric results are available in the openchain.dat and periodicchain.dat for an open and periodic boundary conditions, respectively. The figures below can be reproduced with the `plot.py` script."
+    "A C++ code for exact diagonalizationcan be found in the `heised_cpp` directory, and can be compiled by following the instructions provided with the skeleton code. Numeric results are available in the `openchain.dat` and `periodicchain.dat` for an open and periodic boundary conditions, respectively. The figures below can be reproduced with the `plot.py` script."
    ]
   },
   {