Aiken, L. H., Clarke, S. P., Sloane, D. M., Sochalski, J., & Silber, J. H. (2002). Hospital nurse staffing and patient mortality, nurse burnout, and job dissatisfaction. Journal of the American Medical Association (JAMA), 288(16),
Look up the above article for a really good idea of how staffing issues affect nurse satisfaction, and thus affects patient outcomes (direct correlation between nurses being dissatisfied and higher mortality rates, etc.).
Anything by Linda Aiken would be good.
Here is a list of her publications. She always researches current nursing issues.