Edit README

python-data/README.md

@@ -9,12 +9,12 @@ In this folder you will find all the material used to run the course.
 
 Presentation material is used from the links listed below:
 
-1. [xarray: Introduction to multidimensional arrays]()
-2. [xarray: Plotting and aggregation]()
-3. [xarray: Groupby processing and masking]()
+1. [xarray: Introduction to multidimensional arrays](https://geohackweek.github.io/nDarrays/01-introduction/), [intro to xarray](https://geohackweek.github.io/nDarrays/02-xarray-architecture/) and [label-based indexing](https://geohackweek.github.io/nDarrays/03-label-based-indexing/).
+2. [xarray: Plotting](https://geohackweek.github.io/nDarrays/04-plotting/) and [aggregation](https://geohackweek.github.io/nDarrays/05-aggregation/)
+3. [xarray: Groupby processing](https://geohackweek.github.io/nDarrays/07-groupby-processing/) and [masking](https://geohackweek.github.io/nDarrays/09-masking/)
 4. [cf-python]()
-5. [matplotlib]()
-6. [numpy]()
-7. [NetCDF4]()
+5. [matplotlib](https://matplotlib.org/stable/users/explain/quick_start.html)
+6. [numpy](https://numpy.org/devdocs/user/quickstart.html)
+7. [NetCDF4](https://unidata.github.io/netcdf4-python/#tutorial)
 
 Each of these has an equivalent notebook in the [exercises](/python-data/exercises) folder with the solutions in the [solutions](python-data/solutions) folder.