update

README.md

@@ -33,7 +33,7 @@
   that extend throughout the whole session. 
   
   Data is saved in [nix](https://github.com/G-Node/nix/wiki) format, which uses 
-  [HDF5](https://www.hdfgroup.org/solutions/hdf5/) as a backend. See
+  [HDF5](https://www.hdfgroup.org/solutions/hdf5/) as a backend, see
   > Stoewer A, Kellner CJ, Benda J, Wachtler T and Grewe J (2014). 
   File format and library for neuroscience data and metadata. Front. Neuroinform. 
   Conference Abstract: Neuroinformatics 2014. https://doi.org/10.3389/conf.fninf.2014.18.00027