Brihat Parashara Hora Shastra
रहुश्चेदथवा केतुर्लग्ने कामेऽष्टमे व्यये । मारकेशान्मदे वाऽपि मारकेशेन संयुतः ॥ २२॥
Rahu and Ketu, as Marakas. If Rahu, or Ketu are placed in Tanu, Yuvati, Randhr, or Vyaya Bhava, or happen to be in the 7th from a Marak Lord, or are placed with such a Grah, they acquire powers of killing in their major, or sub-periods.
english translation
rahuzcedathavA keturlagne kAme'STame vyaye । mArakezAnmade vA'pi mArakezena saMyutaH ॥ 22॥
hk transliteration by Sanscript