diff --git a/pkgs/racket-doc/scribblings/reference/evts.scrbl b/pkgs/racket-doc/scribblings/reference/evts.scrbl
index 0923f7531b..62e53ddb55 100644
--- a/pkgs/racket-doc/scribblings/reference/evts.scrbl
+++ b/pkgs/racket-doc/scribblings/reference/evts.scrbl
@@ -15,7 +15,7 @@ A @deftech{synchronizable event} (or just @defterm{event} for short)
 works with the @racket[sync] procedure to coordinate synchronization
 among threads. Certain kinds of objects double as events, including
 ports and threads. Other kinds of objects exist only for their use as
-events.
+events. Racket's event system is based on Concurrent ML @cite{Reppy99}.
 
 At any point in time, an event is either @deftech{ready for
 synchronization}, or it is not; depending on the kind of event and how
diff --git a/pkgs/racket-doc/scribblings/reference/reference.scrbl b/pkgs/racket-doc/scribblings/reference/reference.scrbl
index 476df10720..7132607b73 100644
--- a/pkgs/racket-doc/scribblings/reference/reference.scrbl
+++ b/pkgs/racket-doc/scribblings/reference/reference.scrbl
@@ -186,6 +186,13 @@ The @racketmodname[racket] library combines
              #:location "Principles of Programming Languages"
              #:date "1991")
 
+  (bib-entry #:key "Reppy99"
+             #:author "John H. Reppy"
+             #:title "Concurrent Programming in ML"
+             #:is-book? #t
+             #:location "Cambridge University Press"
+             #:date "1999")
+
   (bib-entry #:key "Shan04"
              #:author "Ken Shan"
              #:title "Shift to Control"
diff --git a/racket/collects/racket/engine.rkt b/racket/collects/racket/engine.rkt
index 8f2fef74c1..e93e6e4239 100644
--- a/racket/collects/racket/engine.rkt
+++ b/racket/collects/racket/engine.rkt
@@ -68,7 +68,9 @@
                                           (alarm-evt (+ timeout (current-inexact-milliseconds))))
                                       (lambda (x)
                                         (log "alarm woke up, waiting to suspend engine" w)
+                                        (log-error "TRYING TIMEOUT")
                                         (semaphore-wait can-stop-lock)
+                                        (log-error "DOING TIMEOUT")
                                         (log "suspending engine" w)
                                         (thread-suspend worker)
                                         (semaphore-post can-stop-lock)