Harris, R., & Pearse, H. (1937). The crown gall disease of nursery stock: III. a progress report on experiments from 1929 to 1937 to determine the relative susceptibility of malling apple stocks and including the production of galls by synthetic growth substances. [n.p.]: Annual Report of the east malling research station.

Harris, R.V., and H.L Pearse. The Crown Gall Disease of Nursery Stock: III. a Progress Report On Experiments From 1929 to 1937 to Determine the Relative Susceptibility of Malling Apple Stocks and Including the Production of Galls By Synthetic Growth Substances. [n.p.]: Annual Report of the east malling research station, 1937.

Harris, R.V., and H.L Pearse. The Crown Gall Disease of Nursery Stock: III. a Progress Report On Experiments From 1929 to 1937 to Determine the Relative Susceptibility of Malling Apple Stocks and Including the Production of Galls By Synthetic Growth Substances. [n.p.]: Annual Report of the east malling research station, 1937.