diff --git a/pygears/_functions.py b/pygears/_functions.py
index 80fefc1..07c6613 100644
--- a/pygears/_functions.py
+++ b/pygears/_functions.py
@@ -16,7 +16,6 @@
 # *                                                                         *
 # ***************************************************************************
 
-from __future__ import division
 from numpy import sin, cos, dot, array, ndarray, vstack, transpose, sqrt
 from numpy.linalg import solve, norm
 
@@ -26,7 +25,8 @@ def reflection(angle):
                  [-sin(2 * angle), -cos(2 * angle)]])
 
     def func(x):
-        # why not use mat @ x???
+        # we do not use matrix-multiplication here because this is meant to work 
+        # on an array of points
         return dot(x, mat)
 
     return func
@@ -50,7 +50,8 @@ def func(x):
 
 def rotation(angle, midpoint=None):
     midpoint = midpoint or [0.0, 0.0]
-    mat = array([[cos(angle), -sin(angle)], [sin(angle), cos(angle)]])
+    mat = array([[cos(angle), -sin(angle)], 
+                 [sin(angle), cos(angle)]])
     midpoint = array(midpoint)
     vec = midpoint - dot(midpoint, mat)
     trans = translation(vec)
@@ -63,7 +64,9 @@ def func(xx):
 
 def rotation3D(angle):
     mat = array(
-        [[cos(angle), -sin(angle), 0.0], [sin(angle), cos(angle), 0.0], [0.0, 0.0, 1.0]]
+        [[cos(angle), -sin(angle), 0.0], 
+         [sin(angle), cos(angle), 0.0], 
+         [0.0, 0.0, 1.0]]
     )
 
     def func(xx):
@@ -74,7 +77,8 @@ def func(xx):
 
 def translation(vec):
     def trans(x):
-        return [x[0] + vec[0], x[1] + vec[1]]
+        return [x[0] + vec[0], 
+                x[1] + vec[1]]
 
     def func(x):
         return array(list(map(trans, x)))
diff --git a/pygears/bevel_tooth.py b/pygears/bevel_tooth.py
index ea1153a..c0a4389 100644
--- a/pygears/bevel_tooth.py
+++ b/pygears/bevel_tooth.py
@@ -16,8 +16,6 @@
 # *                                                                         *
 # ***************************************************************************
 
-from __future__ import division
-from __future__ import division
 from numpy import (
     cos,
     sin,
@@ -28,7 +26,6 @@
     array,
     linspace,
     transpose,
-    vstack,
     sqrt,
 )
 from ._functions import rotation3D, reflection3D, intersection_line_circle
diff --git a/pygears/computation.py b/pygears/computation.py
index bb0e1a8..bf22913 100644
--- a/pygears/computation.py
+++ b/pygears/computation.py
@@ -44,8 +44,9 @@ def root_inv(x):
 
     def d_root_inv(x):
         return 1.0 / np.cos(x) - 1
-
-    alpha_w = find_root(alpha, root_inv, d_root_inv)
+    
+    # use scipy (sp.optimize.minimize(f, f0, df).x) here (as we depent on scipy anyways)
+    alpha_w = find_root(alpha, root_inv, d_root_inv)  
     dist = m * (t1 + t2) / 2 * np.cos(alpha) / np.cos(alpha_w)
     return dist, alpha_w
 
diff --git a/pygears/cycloid_tooth.py b/pygears/cycloid_tooth.py
index 8907ff4..1a9504a 100644
--- a/pygears/cycloid_tooth.py
+++ b/pygears/cycloid_tooth.py
@@ -16,7 +16,6 @@
 # *                                                                         *
 # ***************************************************************************
 
-from __future__ import division
 from numpy import cos, sin, arccos, pi, array, linspace, transpose, vstack
 from ._functions import rotation, reflection
 
diff --git a/pygears/involute_tooth.py b/pygears/involute_tooth.py
index 6733406..834f3db 100644
--- a/pygears/involute_tooth.py
+++ b/pygears/involute_tooth.py
@@ -16,7 +16,6 @@
 # *                                                                         *
 # ***************************************************************************
 
-from __future__ import division
 from numpy import (
     tan,
     cos,
diff --git a/pygears/profile.py b/pygears/profile.py
index 4d8e597..c14a9fe 100644
--- a/pygears/profile.py
+++ b/pygears/profile.py
@@ -1,3 +1,22 @@
+# -*- coding: utf-8 -*-
+# ***************************************************************************
+# *                                                                         *
+# * This program is free software: you can redistribute it and/or modify    *
+# * it under the terms of the GNU General Public License as published by    *
+# * the Free Software Foundation, either version 3 of the License, or       *
+# * (at your option) any later version.                                     *
+# *                                                                         *
+# * This program is distributed in the hope that it will be useful,         *
+# * but WITHOUT ANY WARRANTY; without even the implied warranty of          *
+# * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           *
+# * GNU General Public License for more details.                            *
+# *                                                                         *
+# * You should have received a copy of the GNU General Public License       *
+# * along with this program.  If not, see <http://www.gnu.org/licenses/>.   *
+# *                                                                         *
+# ***************************************************************************
+
+
 import numpy as np
 from .involute_tooth import InvoluteTooth, InvoluteRack
 from .bevel_tooth import BevelTooth