The Bibliotheca Iiddica is part of the Bibliotheca Augustana, a digital library of online texts from the literatures of the world. The Biblioteca Augustana is a project by emeritus professor Ulrich Harsch. See for more information also this Wikipedia entry (in German). The Bibliotheca Iiddica offers:
The links to available online works refer to digital resources such as the Digital Yiddish Library of the Yiddish Book Center and other digital libraries. The advantage of the Bibliotheca Iiddica is that these digital sources are referenced by writer or by century.