Update README.md

Author: adugnag

README.md

@@ -15,6 +15,6 @@ The articles pre-print is available on https://arxiv.org/pdf/2012.03066.pdf
 
 The data used in the paper will be uploaded soon.
 
-##Reference
+## Reference
 
 If you use these scripts please cite our paper as: Mullissa, A.G., Marcos, D., Tuia,D., Herold, M., Reiche, J.,~*deSpeckNet: Generalizing Deep Learning Based SAR Image Despeckling*, IEEE Transactions on Geoscience and Remote Sensing, 2020.