yet another small doc improvement

Author: avehtari

R/loo_compare.R

@@ -61,9 +61,9 @@
 #'   While `khat > 0.5` indicates possibility of outliers, it is also
 #'   possible that both models compared seem to be well specified based
 #'   on model checking, but the pointwise ELPD differences have such thick
-#'   tails that the normal approximation for the sum is not good (note that
-#'   `khat`s in `diag_diff` column are different from the `khat`s in PSIS-LOO
-#'   diagnostic). 
+#'   tails that the normal approximation for the sum is not good (Vehtari et
+#'   al., 2024). Note that `khat`s in `diag_diff` column are different from
+#'   the `khat`s in PSIS-LOO  diagnostic. 
 #'
 #'   The column `diag_elpd` shows diagnostic for the pointwise ELPD
 #'   computations for each model. If `k khat_psis > 0.7` is shown,