<hi xmlns="http://www.tei-c.org/ns/1.0" rend="bold">R Core Team (2017)</hi>: <hi xmlns="http://www.tei-c.org/ns/1.0" rend="italic">R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing</hi>, <ptr xmlns="http://www.tei-c.org/ns/1.0" target="https://www.r-project.org/" />.