Merge pull request #60 from coq-community/add-hal-paper

add HAL paper in meta.yml and README.md

Author: palmskog

README.md

@@ -42,6 +42,7 @@ basic plane topology definitions, and a theory of combinatorial hypermaps.
 - Coq namespace: `fourcolor`
 - Related publication(s):
   - [Formal Proof—The Four-Color Theorem](https://www.ams.org/notices/200811/tx081101382p.pdf) 
+  - [A computer-checked proof of the Four Color Theorem](https://inria.hal.science/hal-04034866/document) 
 
 ## Building and installation instructions
 

meta.yml

@@ -16,6 +16,8 @@ description: |-
 publications:
 - pub_url: https://www.ams.org/notices/200811/tx081101382p.pdf
   pub_title: Formal Proof—The Four-Color Theorem
+- pub_url: https://inria.hal.science/hal-04034866/document
+  pub_title: A computer-checked proof of the Four Color Theorem
 
 authors:
 - name: Georges Gonthier