documentation: philosophy: Add link to "An Excess-Based Economic Model for Resource Allocation in Peer-to-Peer Networks" paper.

This is temporary as we shouldn't rely on links which could
be broken in the future. Best case solutions:
1. bundle all papers in gnunet repository
2. create a dedicated repository which holds all the papers and publications.

1 files changed, 1 insertions, 1 deletions

diff --git a/doc/chapters/philosophy.texi b/doc/chapters/philosophy.texi
index 43059eae1..ade4cc489 100644
--- a/doc/chapters/philosophy.texi
+++ b/doc/chapters/philosophy.texi
@@ -187,7 +187,7 @@ request a (possibly lower) effective priority. Then, they drop the requests
 with the lowest effective priority to satisfy their resource constraints. This
 way, GNUnet's economic model ensures that nodes that are not currently
 considered to have a surplus in contributions will not be served if the
-network load is high. More details can be found in this paper.
+network load is high. More details can be found in @uref{https://gnunet.org/ebe, this paper}.
 
 @node Confidentiality
 @subsection Confidentiality