diff --git a/swh-team/check-contributors b/swh-team/check-contributors
index 668661d..eaea54f 100755
--- a/swh-team/check-contributors
+++ b/swh-team/check-contributors
@@ -1,88 +1,91 @@
 #!/usr/bin/python3
 
 import click
 import logging
 import os
 import subprocess
 import sys
 
 from contextlib import contextmanager
 from pprint import pprint
 
 
 # known git commit author names used by Software Heritage staffers
 SWH_TEAM_AUTHORS = {
     'Antoine Lambert',
     'Antoine Pietri',
     'Antoine R. Dumont (@ardumont)',
+    'Antoine R. Dumont',
     'David Douard',
+    'François Tigeot',
     'moranegg',
     'Morane Otilia Gruenpeter',
     'Nicolas Dandrimont',
+    'Roberto Di Cosmo',
     'Stefano Zacchiroli',
     'Valentin Lorentz',
 }
 
 # path where to look for known, per-repository, non-team contributors
 CONTRIBS_PATH = 'CONTRIBUTORS'
 
 ENCODING = 'utf-8'
 
 
 @contextmanager
 def chdir(path):
     """context manager to execute a code block in a given dir and go back to the
     previous cwd when done
 
     """
     previous_dir = os.getcwd()
     os.chdir(path)
     try:
         yield path
     finally:
         os.chdir(previous_dir)
 
 
 def check_contributors(git_dir, known_contributors):
     """cross-check_contributors all git commit authors against the list of
     known_contributors
 
     Return: list of unknown contributors, if any
 
     """
     with chdir(git_dir):
         contributors = set()  # contributors listed in CONTRIBUTORS file
         if os.path.exists(CONTRIBS_PATH):
             with open(CONTRIBS_PATH, encoding=ENCODING) as f:
                 contributors = {l.rstrip() for l in f}
 
         rc = subprocess.run('git log --pretty=%an | sort -u',
                             shell=True, encoding=ENCODING,
                             capture_output=True, check=True)
         authors = {l for l in rc.stdout.split('\n') if l}
 
     return authors - contributors - known_contributors
 
 
 @click.command()
 @click.argument('paths', nargs=-1)
 def main(paths):
     if not paths:
         paths = ['.']
 
     unknown_contributors = {}
     for path in paths:
         contribs = check_contributors(path, SWH_TEAM_AUTHORS)
         if contribs:  # at least one unknown contributor found for path
             unknown_contributors[path] = contribs
 
     if unknown_contributors:
         logging.error('Unknown contributors:')
         pprint(unknown_contributors, stream=sys.stderr, indent=2)
         sys.exit(1)
     else:
         sys.exit(0)
 
 
 if __name__ == '__main__':
     main()