Quote from the book "Мои скитания"

Suitable for smartphones, Android tablets, e-readers (except Kindle) and many programs

Can be opened on almost any device

Can be opened on any computer

Can be opened on any computer

Opens in Adobe Reader

Suitable for Kindle e-readers and Android apps

Suitable for iOS devices (iPhone, iPad, iMac) and most reading apps

Perfect for iPhone and iPad

Development of FB2 format