1. KNIGFIT, R. L., and ALSTON, F. H. (1969). Developments in apple breeding.Rep. E. Mailing Res. Stn for 1968, 125–32.
2. PRESTON, A. P. (1962). The behaviour of fourteen clonal apple rootstocks in an exposed hill-top orchard.Rep. E. Mailing Res. Stn for 1961, 63–6.