Shiva Purana
योजनानां च पंचाशत्कोटिसंख्याप्रमाणतः॥ ब्रह्मांडस्यैव विस्तारो मुनिभिः परिकीर्तितः॥ १८॥
The extent of the Cosmic Egg is fifty crores of Yojanas as glorified by the sages.
english translation
yojanAnAM ca paMcAzatkoTisaMkhyApramANataH॥ brahmAMDasyaiva vistAro munibhiH parikIrtitaH॥ 18॥
hk transliteration by Sanscript