Published in Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences, in 1886, in volume 103, issue 15, pages 645-647

Published in Compte Rendu, in 1886, in volume 102, pages 1180-1183

Published in Compte Rendu, in 1886, in volume 103, pages 499-501

Published in Compte Rendu, in 1886, in volume 103, pages 760-762