Engelbrecht, J. P., Tropp, R. J., Kuhns, H. D., Green, M. C., Watson, J. G. (2005). Positive Matrix Factorization (PMF) and Chemical Mass Balance (CMB) Receptor Modeling Applied to IMPROVE Data Sets from the Northeastern USA, American Association for Aerosol Research (AAAR) International Specialty Conference: Atlanta, GA, February 8, 2005