Rothberg MB, Zilberberg MD, Pekow PS, Priya A, Haessler S, Belforti R, Skiest D, Lagu T, Higgins TL, Lindenauer PK. Association of guideline-based antimicrobial therapy and outcomes in healthcare-associated pneumonia. J Antimicrob Chemother. 2015 May; 70(5):1573-9.