diff --git a/README.md b/README.md
index 232522d..be7c5ba 100644
--- a/README.md
+++ b/README.md
@@ -34,3 +34,37 @@ additional documentation (the math behind it). This will be published
 in a sister repository in a later stage.
 
 If you have any question(s), please feel free to contact us: info@ascee.nl.
+
+
+## Installation
+
+### Compilation
+
+#### Archlinux
+
+Compiling the code on Archlinux requires the following packages to be available:
+
+- openblas-lapack (AUR)
+- Python 3.7
+- Numpy (Python-numpy)
+- Cython
+
+#### Ubuntu / Linux Mint
+
+*Only tested with Linux Mint 18.04*, we require the following packages for
+compilation:
+
+- build-essential
+- cython
+- python3-numpy
+- libopenblas
+- libclalsadrv-dev
+- libopenblas-base
+- libopenblas-dev
+
+### Dependencies
+
+#### Ubuntu / Linux Mint
+
+*Only tested with Linux Mint 18.04*. The following Dependencies are required
+for Ubuntu:
diff --git a/lasp/__init__.py b/lasp/__init__.py
index e69de29..a921472 100644
--- a/lasp/__init__.py
+++ b/lasp/__init__.py
@@ -0,0 +1,8 @@
+from .lasp_atomic import *
+from .lasp_avstream import *
+from .lasp_common import *
+from .lasp_measurement import *
+from .lasp_octavefilter import *
+from .lasp_slm import *
+from .lasp_weighcal import *
+from .wrappers import *
diff --git a/lasp/lasp_common.py b/lasp/lasp_common.py
index 990ca91..d8f50b5 100644
--- a/lasp/lasp_common.py
+++ b/lasp/lasp_common.py
@@ -7,6 +7,7 @@ Common definitions used throughout the code.
 """
 
 __all__ = ['P_REF', 'FreqWeighting', 'TimeWeighting', 'getTime', 'calfile',
+           'getFreq',
            'W_REF', 'U_REF', 'I_REF']
 
 # Reference sound pressure level
@@ -53,9 +54,11 @@ class TimeWeighting:
     none = (None, 'Raw (no time weighting)')
     uufast = (1e-4, '0.1 ms')
     ufast = (30e-3, '30 ms')
-    fast = (0.125, 'Fast')
-    slow = (1.0, 'Slow')
-    types = (none, uufast, ufast, fast, slow)
+    fast = (0.125, 'Fast (0.125 s)')
+    slow = (1.0, 'Slow (1.0 s)')
+    tens = (10, '10 s')
+    infinite = (np.Inf, 'Infinite')
+    types = (none, uufast, ufast, fast, slow, tens, infinite)
     default = 2
 
     @staticmethod
diff --git a/lasp/wrappers.pyx b/lasp/wrappers.pyx
index c2cfea9..7fd4805 100644
--- a/lasp/wrappers.pyx
+++ b/lasp/wrappers.pyx
@@ -1,8 +1,10 @@
 """
-This file contains the Cython wrapper functions to 
+This file contains the Cython wrapper functions to C implementations.
 """
 include "config.pxi"
 
+__all__ = ['AvPowerSpectra']
+
 setTracerLevel(15)
 cdef extern from "cblas.h":
     int openblas_get_num_threads()
diff --git a/scripts/lasp_calibrate.py b/scripts/lasp_calibrate.py
index 7dbc06b..8f2b094 100755
--- a/scripts/lasp_calibrate.py
+++ b/scripts/lasp_calibrate.py
@@ -5,7 +5,7 @@ Created on Tue Aug 14 12:49:27 2018
 
 @author: J.A. de Jong - ASCEE
 
-Description: calibrate device using measurement
+Description: apply calibration to measurement files.
 
 """
 import numpy as np
@@ -28,7 +28,8 @@ parser.add_argument('--gain-setting', '-g',
 parser.add_argument(
     'fn', help='File name of calibration measurement', type=str)
 
-parser.add_argument('--channel', help='Channel of the device to calibrate, default = 0',
+parser.add_argument('--channel', help='Channel of the device to calibrate, '
+                    + 'default = 0',
                     type=int, default=0)
 
 parser.add_argument('--spl', '-s', help='Applied sound pressure level to the'