Book-length comics take different forms in different cultures. European comics albums are most commonly printed in A4-size colour volumes. In English-speaking countries, bound volumes of comics are called graphic novels and are available in various formats. Despite incorporating the term "novel"—a term normally associated with fiction—"graphic novel" also refers to non-fiction and collections of short works. Japanese comics are collected in volumes called tankōbon following magazine serialization.
What term can mean a non-fiction piece of a collection of short pieces? (If the question is unanswerable, say "unanswerable")
graphic novels