Brihat Samhita
द्वादशदशमएकादशनक्षत्राद्वक्रिते कुजे अश्रुमुखम् । दूषयति रसानुदये करोति रोगानवृष्टिं च ॥ ६-०२ ॥
If Mars should begin to retrograde from the 10th, 11th or 12th constellation from that of his reappearance, such retrograde motion is known as aśrumukha: when Mars should re-appear after his next conjunction with the Sun, juice will be injured and there will be disease and drought.
english translation
dvAdazadazamaekAdazanakSatrAdvakrite kuje azrumukham । dUSayati rasAnudaye karoti rogAnavRSTiM ca ॥ 6-02 ॥
hk transliteration by Sanscript