Hartog, P. J., Rhodes, E. C., & International Institute Examinations Enquiry. English Committee. (1936). An examination of examinations: Being a summary of investigations on the comparison of marks allotted to examination scripts by independent examiners and boards of examiners, together with a section on a viva voce examination (2nd ed., 3rd impression.). Macmillan and Co., Ltd..

Hartog, Philip Joseph, et al. An Examination of Examinations: Being a Summary of Investigations on the Comparison of Marks Allotted to Examination Scripts by Independent Examiners and Boards of Examiners, Together with a Section on a Viva Voce Examination. 2nd ed., 3rd impression. Macmillan and Co., Ltd., 1936.