Rasarnavasudhakara 1.522

1.522

āsāṃ ca madhye vṛttīnāṃ śabda-vṛttis tu bhāratī |
tisro' rtha-vṛttayaḥ śeṣās tac-catasro hi vṛttayaḥ ||

And among these dramatic styles, the verbal style is the Bhāratī;
the remaining three are styles of action—thus there are indeed four styles.