Update README.md

Minor update with link to license

README.md

@@ -4,7 +4,7 @@
 Wrapper around the [Zemax OpticStudio](https://www.zemax.com/pages/opticstudio) API that provides a more pythonic and intuitive way to interact with the ZOS-API through python using a .NET connection. It also takes care of initiating the connection.
 
 ## Waranty and liability
-The code is provided as is, without any warranty. It is solely intended for research purposes. No warranty is given and no rights can be derived from it, as is also stated in the GNU General Public License Version 3.
+The code is provided as is, without any warranty. It is solely intended for research purposes. No warranty is given and no rights can be derived from it, as is also stated in the [GNU General Public License Version 3](https://github.com/MREYE-LUMC/ZOSPy/blob/b26c2627d625f19545159dbf938847a9ebaf5a67/LICENSE.txt).
 
 ## Installing
 
@@ -24,13 +24,13 @@ pip install zospy
 - [Zemax OpticStudio](https://www.zemax.com/pages/opticstudio) (Tested with version 20.3.2)
 
 ## Referencing
-When publishing results obtained with this package, please cite the paper in which the package was first used:
+When publishing results obtained with this package, please cite the paper in which the package was first used:<br>
 van Vught L, Que I, Luyten GPM and Beenakker JWM.
 _Effect of anatomical differences and intraocular lens design on Negative Dysphotopsia._
 JCRS: Sep 06, 2022.
 [doi: [10.1097/j.jcrs.0000000000001054](https://doi.org/10.1097/j.jcrs.0000000000001054) ] [[JCRS](https://journals.lww.com/jcrs/Abstract/9900/Effect_of_anatomical_differences_and_intraocular.107.aspx)]
 
-If a direct reference of the package is also required, reference it using the following DOI:
+If a direct reference of the package is also required, reference it using the following DOI:<br>
 [![DOI](https://zenodo.org/badge/403590410.svg)](https://zenodo.org/badge/latestdoi/403590410)
 
 ## Basic usage