The Gallery Belvedere has digitalized the magazine Ver Sacrum and it is now available as researchable PDF files.
Ver Sacrum ("Sacret Spring" in Latin)! was the publication of the Vienna Secession. Featuring drawings and designs in the Secession Style and literary contributions from distinguished writers from across Europe, Ver Sacrum was devoted to the communication and dissemination of modern art.
Published between 1898 and 1903, Ver Sacrum appeared monthly, but from the third year, it was available twice monthly with a smaller print run.
https://www.belvedere.at/en/forschung/online-ressourcen/ebooks-der-bibliothek