Phaladeepika
अन्योऽन्यमर्द्धहरणं ग्रहयुक्ते तु कारयेत् । नीचेऽर्द्धमस्तगेऽप्यर्द्धहरणं तेषु कारयेत् ॥ २९॥
If a planet be in conjunction with another planet, reduce the period contributed by the planet by half. If the planet be in depression or combustion, in that case also should a reduction of the period by half be made.
english translation
anyo'nyamarddhaharaNaM grahayukte tu kArayet । nIce'rddhamastage'pyarddhaharaNaM teSu kArayet ॥ 29॥
hk transliteration by Sanscript