Shiva Purana
दक्षिणः कथितः प्राणो मध्यस्थं कथयामि ते॥ एकभागगतो वायुप्रवाहो मुखमण्डले॥ ७३॥
The southern life-force is said to be the middle one I shall tell you. The airflow in one part of the face.
english translation
dakSiNaH kathitaH prANo madhyasthaM kathayAmi te॥ ekabhAgagato vAyupravAho mukhamaNDale॥ 73॥
hk transliteration by Sanscript