3 Letters of Reference for NA Program?

I am applying to a NA program which requires 3 letters of reference in its application: two must be from RN's and one must be from an immediate supervisor. Please give me suggestions or tell me if what I have "so far" is adequate.

1st: Immediate supervisor and director of CCU
2nd: Former professor of pathopharmacology (Ph.D. Nursing), who taught
at National Institute of Health. I got an "A" in the class and received
"honors" credit
3rd: Physician who knows how I work and care for his patients in CCU

As for the "physician," is it more appropriate to ask a recommendation from a cardiologist or pulmonologist?

I am applying to a NA program which requires 3 letters of reference in its application: two must be from RN's and one must be from an immediate supervisor. Please give me suggestions or tell me if what I have "so far" is adequate.

1st: Immediate supervisor and director of CCU
2nd: Former professor of pathopharmacology (Ph.D. Nursing), who taught
at National Institute of Health. I got an "A" in the class and received
"honors" credit
3rd: Physician who knows how I work and care for his patients in CCU

As for the "physician," is it more appropriate to ask a recommendation from a cardiologist or pulmonologist?

I will consider a CRNA to give me reference, possibly the one I plan to shadow.