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..
Chicago (17e ed.) BronvermeldingMiller, Robert L., en 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.
MLA (8e ed.) BronvermeldingMiller, Robert L., en Eric Ehrmann. Hummel: The Complete Collector's Guide and Illustrated Reference / by Robert L. Miller and Eric Ehrmann. 2. ed. Portfolio Pr. Corp., 1979.
Let op: Deze citaties zijn niet altijd 100% accuraat.