Update README.md

[ci skip]

Author: jgabry

README.md

@@ -32,7 +32,7 @@ the tutorial [vignettes](https://mc-stan.org/bayesplot/articles/index.html),
 the examples throughout the package [documentation](https://mc-stan.org/bayesplot/reference/index.html), 
 and the paper _Visualization in Bayesian workflow_:
 
-* Gabry et al. (2019). Visualization in Bayesian workflow. 
+* Gabry J, Simpson D, Vehtari A, Betancourt M, Gelman A (2019). Visualization in Bayesian workflow. 
 _J. R. Stat. Soc. A_, 182: 389-402. doi:10.1111/rssa.12378. 
 ([journal version](https://rss.onlinelibrary.wiley.com/doi/full/10.1111/rssa.12378),
 [arXiv preprint](https://arxiv.org/abs/1709.01449),