Shiva Purana
हंसन्यासं प्रकुर्वीत शिवशास्त्रे यथोदितम् ॥ बीजं विभज्य हंसस्य नेत्रयोर्घ्राणयोरपि ॥ ३९ ॥
One should perform the swan-nyasa as described in the scriptures of Lord Śiva. After dividing the seed into the swan’s eyes and sense of smell,
english translation
haMsanyAsaM prakurvIta zivazAstre yathoditam ॥ bIjaM vibhajya haMsasya netrayorghrANayorapi ॥ 39 ॥
hk transliteration by Sanscript