I want to know the answer to the following question:
In what year was  Du "Cubisme" published?
All the background I'm provided with is that "Two Women (a sculpture now lost), in addition to the highly abstract paintings by Kupka, Amorpha (The National Gallery, Prague), and Picabia, La Source, The Spring (Museum of Modern Art, New York).". Is that enough to answer the question?
Answer: no