Shiva Purana

siva.sh/siva-purana/saturda-samhita/18/27

एकादशैते रुद्रास्तु सुरभतिनयाः स्मृताः ।। देवकार्य्यार्थमुत्पन्नाश्शिवरूपास्सुखास्पदम् ।। २७ ।।

sanskrit

The eleven Rudras born of Surabhī, They were born for the aid to the gods. They are identical with Śiva and the cause of happiness.

english translation

ekAdazaite rudrAstu surabhatinayAH smRtAH || devakAryyArthamutpannAzzivarUpAssukhAspadam || 27 ||

hk transliteration by Sanscript