求翻译：由于有价值文献的阙如，研究者在诸多方面尚未达成统一的看法，比如作品的创作时间。目前学术界有三种观点：宋神宗熙宁三年前后；宋徽宗宣和年间，不早于宣和二年，宋高宗绍兴年间。笔者依据图中所画牲畜的数量，尤其是驴和猪的数量，再结合北宋京师开封驴、马、猪等牲畜的饲养状况，以及驴马在交通运输业的运用情况，认为《清明上河图》的创作不晚于宋神宗时期。是什么意思？

As valuable literature lacking, researchers in many areas not yet reached a unified view, such as the creation of works of the time. Currently there are three academic point of view: Ancestor Xining after three years; Huizong Vision and years and years not earlier than announced, Song Emperor Shaoxi

Because of the valuable literature lacking, researchers in many areas has not yet reached a unified view of works, such as the creative time. At present there are 3 academics view: Song God cases; ( 1101-1125) Hee-sun before and after 3 years and years, no earlier than 2 years, and in the Shaoxing S

Due to the lack of valuable documents, researchers in many aspects have not yet reached a unified view, such as the creation of the work time. Currently academia has three views: before and after the three-year reign XI-Ning; Emperor Huizong Munenobu and years, not earlier than the vision and the se