请用符合高级英文文献中学术规范的语句改写以下段落，并注意加上语句连接词：With the depth of research, the study on the relationship between real estate investment and economic growth has been gradually extended to the spatial scope. (2014) [24] verify the existence, degree of aggregat...-DPDK中文网

As research on the relationship between real estate investment and economic growth has deepened, attention has increasingly turned to its spatial implications. For instance, (2014) [24] employed the Moran index to calculate unconventional spatial agglomeration of real estate development investment and verified the existence, degree of aggregation, and structure of such phenomena. Utilizing a CSAD non-linear model, they also confirmed the presence of a “herd effect” as an explanation for unconventional spatial aggregation. Similarly, (2014) [25] demonstrated significant spatial correlation between real estate investment in 70 large and medium-sized cities in China and highlighted its contribution to economic growth in middle, eastern, and western regions while acknowledging regional differences. In contrast, (2018) [26] revealed stronger cross-regional spatial correlation in real estate investment along with structural differences arising from geographical location factors and socio-economic characteristics. Building upon these findings, (2020) [27] demonstrated that there is spatial spillover of the economic growth effect of real estate investment whereby the flow of real estate investment factors generates this effect promoting economic growth. Finally, (2020) [28] utilized a spatial Durbin model to explore regional characteristics of economic growth driven by real estate investment along with its spatial spillover effects. Their results indicate that there is indeed a spatial spillover effect and varying degrees of dependence on local economies regarding real estate investment across different regions with greater dependence on direct city roles in the eastern region versus indirect roles in the central region.