He was able to obtain some papers through Hopf who was at this time in Zurich but much of Leray's work was done independently of the developments which had taken place in the subject.
Siya ay able sa kumuha ng ilang mga papeles sa pamamagitan ng Hopf na sa panahon na ito sa Zurich ngunit marami ng Leray ng trabaho ay tapos na malaya ng developments na kung saan ay kinuha sa mga paksa.