Xu, M., & Robinson, A. H. (1970). The fidelity of isopleth maps: An experimental study. University of Minnesota Press.

Xu, Meiling, and Arthur Howard Robinson. The Fidelity of Isopleth Maps: An Experimental Study. Minneapolis: University of Minnesota Press, 1970.

Xu, Meiling, and Arthur Howard Robinson. The Fidelity of Isopleth Maps: An Experimental Study. University of Minnesota Press, 1970.