Find the number of participants in detail and its limitations for the given scientific papers: Xiong, Lilin, Xiao Huang, Jie Li, Peng Mao, Xiang Wang, Rubing Wang, & Meng Tang. "Impact of indoor physical environment on learning efficiency in different types of tasks: A 3 4 3 full factorial design analysis."International journal of environmental research and public health15, no. 6 (2018): 1256.

Brink, Henk W., Loomans, M. G., Mobach M. P., and Kort, H. S. . "Classrooms' indoor environmental conditions affecting the academic achievement of students and teachers in higher education: A systematic literature review."Indoor air31.2 (2021): 405-425.