To cite TestDesign in publications, use:

Choi S, Lim S, van der Linden W (2021). “TestDesign: An optimal test design approach to constructing fixed and adaptive tests in R.” Behaviormetrika. doi: 10.1007/s41237-021-00145-9.

Corresponding BibTeX entry:

  @Article{,
    title = {{TestDesign}: An optimal test design approach to
      constructing fixed and adaptive tests in R},
    author = {Seung W. Choi and Sangdon Lim and Wim J. {van der
      Linden}},
    year = {2021},
    doi = {10.1007/s41237-021-00145-9},
    journal = {Behaviormetrika},
  }