Shiva Purana
एवं पक्षौ स्थितौ द्वौ तु समासात्सुरसुंदरि ॥ शुचिर्भूत्वा स्मरन्देवं सुस्नातस्संयतेन्द्रियः ॥ ३१ ॥
O beautiful goddess, in brief there are two fortnights. In these one shall take bath and be clear, remember the lord with controlled senses.
english translation
evaM pakSau sthitau dvau tu samAsAtsurasuMdari ॥ zucirbhUtvA smarandevaM susnAtassaMyatendriyaH ॥ 31 ॥
hk transliteration by Sanscript