Update download URLs

gpaw/README.md

@@ -22,8 +22,14 @@ respectively.
 
 ### Download
 
-GPAW is freely available under the GPL license at:
-  https://gitlab.com/gpaw/gpaw
+GPAW is freely available under the GPL license. The source code can be
+downloaded from the [Git repository](https://gitlab.com/gpaw/gpaw) or as
+a tar package for each release from [PyPi](https://pypi.org/simple/gpaw/).
+
+For example, to get version 1.4.0 using git:
+```bash
+git clone -b 1.4.0 https://gitlab.com/gpaw/gpaw.git
+```
 
 
 ### Install
@@ -42,9 +48,9 @@ Benchmarks
 
 ### Download
 
-The benchmark set is available in the [benchmark](benchmark/) directory or,
-for download, either directly from the
-[git repository](https://github.com/mlouhivu/gpaw-benchmarks/tree/prace)
+The benchmark set is available in the [benchmark/](benchmark/) directory or
+alternatively, for download, either directly from the development
+[Git repository](https://github.com/mlouhivu/gpaw-benchmarks/tree/prace)
 or from the PRACE RI website (http://www.prace-ri.eu/ueabs/).
 
 To download the benchmarks, use e.g. the following command: