Brihat Parashara Hora Shastra
चन्द्राज्जामित्रगे शुक्रे शुक्राज्जामित्रगे शनौ । वत्सरेऽष्टादशे प्राप्ते विवाहं लभते नरः ॥ २७॥
Should Śukr be in Yuvati from Candr, while Śani is in Yuvati from Śukr, marriage will be in the 18th year.
english translation
candrAjjAmitrage zukre zukrAjjAmitrage zanau । vatsare'STAdaze prApte vivAhaM labhate naraH ॥ 27॥
hk transliteration by Sanscript