Sons

On Rama’s instructions,Bharata was sent by Rama to kill a wicked gandharva, a singer of heaven named Shailusha, who lived on the banks of the river Indus with his sons. Bharata killed them and built two cities there,

1. Takshashila and 
2. Pushkaravati. 

In Takshashila Bharata established his son Ataksha as king and in Pushkaravati he made his son pushkara the king.

Source Agni Puran

https://www.google.com/search?q=Taksha+Pushkala