.X set epub-uuid very-unique-identifier
.X set document-title Title
.Pt Part1
.Ch Chap1
Text.
.Ch Chap2
Text.
.Sh Section1
Text.
.Sh Section2
Text.
.Ss Subsection1
Text.
.Pt Part2
.Ch Chap3
Text.
.Sx Section2
.Sx Chap1
.Sx Part2