diff --git a/collects/scribblings/reference/fixnums.scrbl b/collects/scribblings/reference/fixnums.scrbl
index 4ac824f4a9..0028ce1332 100644
--- a/collects/scribblings/reference/fixnums.scrbl
+++ b/collects/scribblings/reference/fixnums.scrbl
@@ -93,7 +93,7 @@ Safe versions of @racket[unsafe-fx->fl] and @racket[unsafe-fl->fx].}
 
 @; ------------------------------------------------------------
 
-@section{Fixnum Vectors}
+@section[#:tag "fxvectors"]{Fixnum Vectors}
 
 A @deftech{fxvector} is like a @tech{vector}, but it holds only
 @tech{fixnums}. The only advantage of a @tech{fxvector} over a
diff --git a/collects/scribblings/reference/flonums.scrbl b/collects/scribblings/reference/flonums.scrbl
index 07458ea7c4..d97e49af1f 100644
--- a/collects/scribblings/reference/flonums.scrbl
+++ b/collects/scribblings/reference/flonums.scrbl
@@ -133,7 +133,7 @@ inexact.}
 
 @; ------------------------------------------------------------------------
 
-@section{Flonum Vectors}
+@section[#:tag "flvectors"]{Flonum Vectors}
 
 A @deftech{flvector} is like a @tech{vector}, but it holds only
 inexact real numbers. This representation can be more compact, and