Brihat Samhita
यद्येको यदि बहवः किं अनेन फलं तु सर्वथा वाच्यम् । उदयास्तमयैः स्थानैः स्पर्शैराधूमनैर्वर्णैः । ११-०६ ॥
Whether there is one Ketu or many, the effects to be described are various and these effects depend on their reappearance or disappearance (at particular times and places), their positions, the heavenly bodies with which they might appear to be in contact and on their colours.
english translation
yadyeko yadi bahavaH kiM anena phalaM tu sarvathA vAcyam । udayAstamayaiH sthAnaiH sparzairAdhUmanairvarNaiH । 11-06 ॥
hk transliteration by Sanscript