pandoc --from markdown --to epub3  \
 epub/title.txt \
 _chapters/00_about.md \
 _chapters/01_set.md \
 _chapters/02_category.md \
 _chapters/03_monoid.md \
 _chapters/04_order.md \
 _chapters/05_logic.md \
 _chapters/10_functors.md \
 epub/title.txt \
 --output book.epub \
 --toc \
 --epub-cover-image=cover_print.png \
 --resource-path=_chapters/02_category \
 --css=epub/epub-style.css