Shiva Purana
पृथक्प्रयोज्या यद्येते बिंदुनादविभूषिताः ॥ अर्धचन्द्रनिभो बिंदुर्नादो दीपशिखाकृतिः ॥ ४४ ॥
If these are not decorated with dots, they should be used separately. The sound of a dot resembling a crescent moon resembled the flame of a lamp.
english translation
pRthakprayojyA yadyete biMdunAdavibhUSitAH ॥ ardhacandranibho biMdurnAdo dIpazikhAkRtiH ॥ 44 ॥
hk transliteration by Sanscript