Rendiconti del Circolo Matematico di PalermoDecember 1892, Volume 6, Supplement 1, pp 35–35 | Cite asBulletin international de ľAcadémie des Sciences de CracovieArticleFirst Online: 21 December 2008 7 Downloads This is a preview of subscription content, log in to check access.Copyright information© Springer 1892