diff --git a/docs/api_reference/src/quantities.tex b/docs/api_reference/src/quantities.tex
index b66d8b25f..149280584 100644
--- a/docs/api_reference/src/quantities.tex
+++ b/docs/api_reference/src/quantities.tex
@@ -3861,7 +3861,14 @@
 
 \pnum
 \returns
-\tcode{is_\placeholdernc{F}(q <=> zero())}\irefcpp{compare.syn}.
+\begin{itemize}
+\item
+If \tcode{\placeholdernc{F}} is \tcode{eq}, returns \tcode{q == zero()}.
+\item
+Otherwise, if \tcode{\placeholdernc{F}} is \tcode{neq}, returns \tcode{q != zero()}.
+\item
+Otherwise, returns \tcode{is_\placeholdernc{F}(q <=> zero())}\irefcpp{compare.syn}.
+\end{itemize}
 
 \pnum
 \remarks