To cite package 'latdiag' in publications use:

Michael Dewey (2018). latdiag: diagrams for latent trait models. R package version 0.2-4.

Corresponding BibTeX entry:

  @Manual{,
    title = {latdiag: diagrams for latent trait models},
    author = {Michael Dewey},
    year = {2018},
    note = {R package version 0.2-4},
  }