APA   Click to copy
Greiff, S. (2020). Technology-based assessment in 21st century education. In R. Zender, D. Ifenthaler, T. Leonhardt, & C. Schumacher (Eds.) (pp. 21–22). Bonn: Gesellschaft für Informatik.

Chicago/Turabian   Click to copy
Greiff, S. “Technology-Based Assessment in 21st Century Education.” In , edited by R. Zender, D. Ifenthaler, T. Leonhardt, and C. Schumacher, 21–22. Proceedings of the 18th Annual Conference of GI Educational Technologies Special Interest Group (DELFI). Bonn: Gesellschaft für Informatik, 2020.

MLA   Click to copy
Greiff, S. Technology-Based Assessment in 21st Century Education. Edited by R. Zender et al., Gesellschaft für Informatik, 2020, pp. 21–22.

@inbook{greiff2020a,
  title = {Technology-based assessment in 21st century education},
  year = {2020},
  address = {Bonn},
  pages = {21-22},
  publisher = {Gesellschaft für Informatik},
  series = {Proceedings of the 18th Annual Conference of GI Educational Technologies Special Interest Group (DELFI)},
  author = {Greiff, S.},
  editor = {Zender, R. and Ifenthaler, D. and Leonhardt, T. and Schumacher, C.}
}