Since the canons of criticism are highly susceptible to interpretation, and at times even contradict each other, they may be employed to justify a result that fits the textual critic's aesthetic or theological agenda. Starting in the 19th century, scholars sought more rigorous methods to guide editorial judgment. Best-text editing (a complete rejection of eclecticism) became one extreme. Stemmatics and copy-text editing – while both eclectic, in that they permit the editor to select readings from multiple sources – sought to reduce subjectivity by establishing one or a few witnesses presumably as being favored by "objective" criteria.[citation needed] The citing of sources used, and alternate readings, and the use of original text and images helps readers and other critics determine to an extent the depth of research of the critic, and to independently verify their work.