Skandapurana 16.97.8

16.97.8

vṛṣabhastatra dātavyaḥ saṃpūrṇaphalahetave ..
evamekādaśa proktā rudrāḥ prābhāsamāśritāḥ ..
nityaṃ pūjyāśca vaṃdyāśca kṣetrasya phalamīpsubhiḥ .. 8 ..

A bull should be given there for the sake of the complete fruit. / Thus eleven Rudras dwelling in Prabhāsa have been proclaimed; / they must be constantly worshipped and revered by those desiring the fruit of the sacred field. 8