Brihat Parashara Hora Shastra
आत्माकारकभागेभ्यो न्यूनांशोऽमात्यकारकः । तस्मान्न्यूनांशको भ्राता तन्न्यूनोमातृसंज्ञकः ॥ १३॥
Other Karakas. The Grah next to Atma Karak in terms of longitude is called Amatya Karak.
english translation
AtmAkArakabhAgebhyo nyUnAMzo'mAtyakArakaH । tasmAnnyUnAMzako bhrAtA tannyUnomAtRsaMjJakaH ॥ 13॥
hk transliteration by Sanscript