billing for nurse practitioner/hospital codes

If nurse practitioner sees patients in the hospital and all necessary documentation has been obtained, am I allowed to bill under him/her or do I have to bill under the physician in which him/her is in collaboration?

re: billing for nurse practitioner/hospital codes

Nurse Practitioners, unless authorized by their state regulations, should not submit claims for inpatient hospital admissions (CPT Codes 99221 – 99223: Initial Hospital Care, New or Established Patient). ... NPs who do not have admitting privileges based on state regulations cannot bill for the admission.

Incident to can be used to bill NP visits.