diff --git a/README.md b/README.md
index 5ac6899..4c6ce53 100644
--- a/README.md
+++ b/README.md
@@ -6,11 +6,11 @@ MPB is a free and open-source software package for computing electromagnetic ban
 ## Features
 
 -   **Free and open-source software** under the [GNU GPL](https://en.wikipedia.org/wiki/GNU_General_Public_License).
--   Complete **scriptability** via [Python](Python_Tutorial) or [Scheme](Scheme_User_Interface) APIs.
+-   Complete **scriptability** via [Python](doc/docs/Python_Tutorial.md) or [Scheme](doc/docs/Scheme_Tutorial.md) APIs.
 -   Portable to any Unix-like system such as [Linux](https://en.wikipedia.org/wiki/Linux), [macOS](https://en.wikipedia.org/wiki/MacOS), and [FreeBSD](https://en.wikipedia.org/wiki/FreeBSD).
 -   Distributed memory **parallelism** on any system supporting the [MPI](https://en.wikipedia.org/wiki/Message_Passing_Interface) standard.
 -   Fully-vectorial **1d, 2d, 3d** calculations. Iterative eigensolver techniques are employed to make large calculations possible.
--   **Direct, frequency-domain eigensolver** as opposed to indirect methods, e.g. time-domain. This means that you get both eigenvalues (frequencies) and eigenstates (electromagnetic modes) at the same time. See [comparison of time-domain and frequency-domain techniques](Introduction.md#frequency-domain-vs-time-domain).
+-   **Direct, frequency-domain eigensolver** as opposed to indirect methods, e.g. time-domain. This means that you get both eigenvalues (frequencies) and eigenstates (electromagnetic modes) at the same time. See [comparison of time-domain and frequency-domain techniques](doc/docs/Introduction.md#frequency-domain-vs-time-domain).
 -   **Targeted eigensolver**. Iterative eigensolvers normally compute states (harmonic modes) with the lowest few frequencies. MPB can alternatively compute the modes whose frequencies are closest to a specified target frequency. This greatly reduces the number of bands that must be computed in guided or resonant mode calculations.
 -   Support for arbitrary, **anisotropic** dielectrics including **gyrotropic/magneto-optic** materials and **non-orthogonal** unit cells. Lossy and wavelength-dependent $\varepsilon$ and $\mu$ are not supported.
 -   Field output in the [HDF5](https://support.hdfgroup.org/HDF5/) data format.
diff --git a/mpb/mpb.h b/mpb/mpb.h
index 2e2187c..5e7f146 100644
--- a/mpb/mpb.h
+++ b/mpb/mpb.h
@@ -18,6 +18,7 @@
 #ifndef MPB_H
 #define MPB_H
 
+#include <string.h>
 #include <maxwell.h>
 #include <ctl-io.h>
 #include <ctlgeom.h>