Miller, R. L., & Ehrmann, E. (1979). Hummel: The complete collector's guide and illustrated reference / by Robert L. Miller and Eric Ehrmann (2. ed.). Portfolio Pr. Corp..
Citazione stile Chigago Style (17a edizione)Miller, Robert L., e Eric Ehrmann. Hummel: The Complete Collector's Guide and Illustrated Reference / by Robert L. Miller and Eric Ehrmann. 2. ed. Huntington, NY: Portfolio Pr. Corp., 1979.
Citatione MLA (8a ed.)Miller, Robert L., e Eric Ehrmann. Hummel: The Complete Collector's Guide and Illustrated Reference / by Robert L. Miller and Eric Ehrmann. 2. ed. Portfolio Pr. Corp., 1979.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.