According to the author's preface to this document, Ullerston's Petitiones was composed at the request of Bishop Robert Hallum for the use of the English delegation at the Council of Pisa of 1409. Because the causa reformationis was not really addressed at that council, this tract was subsequently employed as a framework for English reform efforts at Constance.
The best study of this text remains Margaret M. Harvey's unpublished doctoral dissertation: "English views on the reforms to be undertaken in the general councils (1400-1418) with special reference to the proposals made by Richard Ullerston" (Oxford D.Phil., 1964).
Harvey noted the existence of several manuscript copies of this tract, but explained that the printed edition by Hermann von der Hardt, although not ideal, is an adequate version of the text:
Petitiones quoad reformationem ecclesiae militantis Richardi Ullerston
The transcription was carried out by Chris L. Nighman.
For information on the editorial principles employed and the electronic format of this text, check the Project Description page.