Readers should cite both the Bio-protocol preprint and the original research article where this protocol was used:

Zhang, H, Zhang, S, He, X and Duan, J(2021). 1.2. Differentiation of iPSCs into neural progenitor cells (NPCs). Bio-protocol Preprint. bio-protocol.org/prep1271.
Zhang, S., Zhang, H., Zhou, Y., Qiao, M., Zhao, S., Kozlova, A., Shi, J., Sers, A. R., Wang, G., Luo, K., Sengupta, S., West, S., Qian, S., Streit, M., Avramopoulos, D., Cowan, C. A., Chen, M., Pang, Z. P., Gejman, P. V., He, X. and Duan, J.(2020). Allele-specific open chromatin in human iPSC neurons elucidates functional disease variants . Science 369(6503). DOI: 10.1126/science.aay3983