diff --git a/config.default.yaml b/config.default.yaml
index 7a443a03..d2bf6159 100755
--- a/config.default.yaml
+++ b/config.default.yaml
@@ -154,6 +154,7 @@ renewable:
     # sector: The economic potential of photovoltaics and concentrating solar
     # power." Applied Energy 135 (2014): 704-720.
     # This correction factor of 0.854337 may be in order if using reanalysis data.
+    # for discussion refer to https://github.com/PyPSA/pypsa-eur/pull/304
     # correction_factor: 0.854337
     corine: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,
              14, 15, 16, 17, 18, 19, 20, 26, 31, 32]