<affiliation wicri:level="4"><country xml:lang="fr">Royaume-Uni</country>
<wicri:regionArea>Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street,¶Cambridge CB3 9EW, UK. E-mail: m.a.walton@damtp.cam.ac.uk</wicri:regionArea>
<orgName type="university">Université de Cambridge</orgName>
<placeName><settlement type="city">Cambridge</settlement>
<region type="country">Angleterre</region>
<region type="région" nuts="1">Angleterre de l'Est</region>
</placeName>
</affiliation>