remove 'please cite', fix wording

content/index.txt

@@ -24,14 +24,11 @@ summarized as follows:
     :width: 90%
 
 Kwant was designed to be easy to use: for example the program that generates
-the right panel of the image above is only 42 lines long. It is also accessible
-for people without expertise in numerics. To aid that, it is provided along
-with a detailed hand-on `tutorial </doc/1.0/tutorial/>`_ and the Kwant `paper
-</paper>`_, which describes the guiding principles underlying its design.
-
-Kwant is provided to the physics community as an open source free software (we
-merely ask you to cite Kwant article in scientific publications using
-Kwant). Below a few research applications of Kwant are shown.
+the right panel of the image above is only 42 lines long. Kwant is also
+accessible for people without expertise in numerics. To aid that, it is
+provided along with a detailed hand-on `tutorial </doc/1.0/tutorial/>`_ and the
+Kwant `paper </paper>`_, which describes the guiding principles underlying its
+design.
 
 Examples of the use of Kwant
 ----------------------------