diff --git a/scripts/build_cop_profiles.py b/scripts/build_cop_profiles.py
index 94cc8fb4..91d03469 100644
--- a/scripts/build_cop_profiles.py
+++ b/scripts/build_cop_profiles.py
@@ -12,6 +12,7 @@ sink.
 
 The quadratic regression used is based on Staffell et al. (2012)
 
+
 https://doi.org/10.1039/C2EE22653G.
 """
 
diff --git a/scripts/build_gas_network.py b/scripts/build_gas_network.py
index 907b151c..a9f28e0d 100644
--- a/scripts/build_gas_network.py
+++ b/scripts/build_gas_network.py
@@ -29,6 +29,7 @@ def diameter_to_capacity(pipe_diameter_mm):
 
     Based on p.15 of
 
+
     https://gasforclimate2050.eu/wp-content/uploads/2020/07/2020_European-Hydrogen-Backbone_Report.pdf
     """
     # slopes definitions