Shiva Purana
अथास्य पार्श्वतः कृष्णाः कृष्णस्नानानुलेपनाः॥ चत्वारस्तु महात्मानः संबभूवुः कुमारकाः॥२८॥
Then from his sides sprang up four noble-souled sons all of whom were black in colour and had black toilet and unguent articles.
english translation
athAsya pArzvataH kRSNAH kRSNasnAnAnulepanAH॥ catvArastu mahAtmAnaH saMbabhUvuH kumArakAH॥28॥
hk transliteration by Sanscript