Astanga Hrudaya
तत्रस्थाश्च विलम्बेरन् भूयो हेतुप्रतीक्षिणः। ते कालादिबलं लब्ध्वा कुपयन्त्यन्याश्रयेष्वपि॥१९॥
When Doshas move from one place to other, they remain there for some time, waiting for an exciting factor. After deriving strength by season, time etc, they get further aggravated and move to other places as well.
english translation
tatrasthAzca vilamberan bhUyo hetupratIkSiNaH। te kAlAdibalaM labdhvA kupayantyanyAzrayeSvapi॥19॥
hk transliteration by Sanscript