To cite opentripplanner package in publications use:
Malcolm Morgan, Marcus Young, Robin Lovelace, Layik Hama (2019). “OpenTripPlanner for R.” Journal of Open Source Software, 4(44), 1926. doi: 10.21105/joss.01926.
Corresponding BibTeX entry:
@Article{, title = {OpenTripPlanner for R}, author = {{Malcolm Morgan} and {Marcus Young} and {Robin Lovelace} and {Layik Hama}}, journal = {Journal of Open Source Software}, year = {2019}, volume = {4}, number = {44}, pages = {1926}, doi = {10.21105/joss.01926}, }