Given the task definition, example input & output, solve the new input case.
This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
Example: Passage: The French and Indian War (17541763) was the North American theater of the worldwide Seven Years' War. The war was fought between the colonies of British America and New France, with both sides supported by military units from their parent countries of Great Britain and France, as well as Native American allies. At the start of the war, the French North American colonies had a population of roughly 60,000 European settlers, compared with 2 million in the British North American colonies. The outnumbered French particularly depended on the Indians. Long in conflict, the metropole nations declared war on each other in 1756, escalating the war from a regional affair into an intercontinental conflict. Question: When was the French and Indian War?
Output: 1754-1763
It is a common convention to write (start year-end year) beside a historical event to understand when the event happened. We can observe a similar notation from the passage to conclude that the French and Indian War happened during 17541763. Therefore, the answer is 17541763.

New input case for you: Passage: European comics studies began with Topffer's theories of his own work in the 1840s, which emphasized panel transitions and the visualverbal combination. No further progress was made until the 1970s. Pierre Fresnault-Deruelle then took a semiotics approach to the study of comics, analyzing textimage relations, page-level image relations, and image discontinuities, or what Scott McCloud later dubbed "closure". In 1987, Henri Vanlier introduced the term multicadre, or "multiframe", to refer to the comics a page as a semantic unit. By the 1990s, theorists such as Benoit Peeters and Thierry Groensteen turned attention to artists' poietic creative choices. Thierry Smolderen and Harry Morgan have held relativistic views of the definition of comics, a medium that has taken various, equally valid forms over its history. Morgan sees comics as a subset of "les litteratures dessinees" (or "drawn literatures"). French theory has come to give special attention to the page, in distinction from American theories such as McCloud's which focus on panel-to-panel transitions. Since the mid-2000s, Neil Cohn has begun analyzing how comics are understood using tools from cognitive science, extending beyond theory by using actual psychological and neuroscience experiments. This work has argued that sequential images and page layouts both use separate rule-bound "grammars" to be understood that extend beyond panel-to-panel transitions and categorical distinctions of types of layouts, and that the brain's comprehension of comics is similar to comprehending other domains, such as language and music. Question: In the 1840s, Topffer wrote theories about whose work?
Output:
his own