If an eBook does not have page numbers or gives a percentage, provide the chapter or section information.
When referring to a particular chapter, type chapter or ch followed by the relevant chapter number, e.g.
(Smith, 2020, chapter 6) or (Smith, 2020, ch 6)
When referring to a particular section, type section or s followed by the relevant section number, e.g.
(Jones, 2020, section 3) or (Jones, 2020, s 3)
For more information see Referencing Guide