Citations refer to the original publication, not to a Scieee localized version.
Bluntschli, J. C. (1880). Derecho publico universal. T. 3. Madrid : F. Góngora y Compañía, 1880. https://idus.us.es/items/0a4e10bf-2f12-49bd-8547-c0639f87b6fb
Bluntschli, Johann Caspar, 1808-1881. Derecho publico universal. T. 3. Madrid : F. Góngora y Compañía, 1880, 1880. https://idus.us.es/items/0a4e10bf-2f12-49bd-8547-c0639f87b6fb.
Bluntschli, Johann Caspar, 1808-1881. Derecho publico universal. T. 3. Madrid : F. Góngora y Compañía, 1880, 1880. https://idus.us.es/items/0a4e10bf-2f12-49bd-8547-c0639f87b6fb.
Bluntschli, J. C. (1880) Derecho publico universal. T. 3. Madrid : F. Góngora y Compañía, 1880. Available at: https://idus.us.es/items/0a4e10bf-2f12-49bd-8547-c0639f87b6fb.
J. C. Bluntschli, “Derecho publico universal. T. 3,” Madrid : F. Góngora y Compañía, 1880, 1880. [Online]. Available: https://idus.us.es/items/0a4e10bf-2f12-49bd-8547-c0639f87b6fb
@misc{bluntschli1880derecho,
author = {Bluntschli, Johann Caspar, 1808-1881},
title = {Derecho publico universal. T. 3},
year = {1880},
publisher = {Madrid : F. Góngora y Compañía, 1880},
url = {https://idus.us.es/items/0a4e10bf-2f12-49bd-8547-c0639f87b6fb}
}
The source metadata has no journal, volume or pages. Add them from the original publication if your citation needs them.