diff --git a/doc/funcref.sgml b/doc/funcref.sgml
index 0fe1ce847..4a6e13c5e 100644
--- a/doc/funcref.sgml
+++ b/doc/funcref.sgml
@@ -4,7 +4,7 @@
 <title>cc65 function reference
 <author><url url="mailto:uz@cc65.org" name="Ullrich von Bassewitz">,<newline>
 <url url="mailto:greg.king5@verizon.net" name="Greg King">
-<date>2018-02-07
+<date>2018-05-23
 
 <abstract>
 cc65 is a C compiler for 6502 based systems. This function reference describes
@@ -206,6 +206,7 @@ function.
 <item><ref id="cbm_k_tksa" name="cbm_k_tksa">
 <item><ref id="cbm_k_udtim" name="cbm_k_udtim">
 <item><ref id="cbm_k_unlsn" name="cbm_k_unlsn">
+<item><ref id="cbm_k_untlk" name="cbm_k_untlk">
 <!-- <item><ref id="cbm_load" name="cbm_load"> -->
 <!-- <item><ref id="cbm_open" name="cbm_open"> -->
 <!-- <item><ref id="cbm_opendir" name="cbm_opendir"> -->
@@ -358,6 +359,9 @@ function.
 
 <sect1><tt/em.h/<label id="em.h"><p>
 
+This header file contains definitions for extended memory access,
+see also <tt>testcode/lib/em-test.c</tt> and <tt>samples/multidemo.c</tt>.
+
 <itemize>
 <item><ref id="em_commit" name="em_commit">
 <item><ref id="em_copyfrom" name="em_copyfrom">
@@ -544,8 +548,8 @@ It does not declare any functions.
 
 <sect1><tt/serial.h/<label id="serial.h"><p>
 
-The <tt/serial.h/ header file contains definitions for initializing serial
-communication.
+This header file contains definitions for initializing serial
+communication, see also <tt>testcode/lib/ser-test.c</tt>.
 
 <itemize>
 <item><ref id="ser_close" name="ser_close">
@@ -2088,7 +2092,7 @@ only be used in presence of a prototype.
 </itemize>
 <tag/Availability/cc65
 <tag/See also/
-<ref id="cbm_k_unlsn" name="cbm_k_unlsn">,
+<ref id="cbm_k_unlsn" name="cbm_k_unlsn">
 <tag/Example/None.
 </descrip>
 </quote>
@@ -2342,9 +2346,6 @@ bus. Only devices previously commanded to LISTEN are affected. This
 function is normally used after the host computer is finished sending data
 to external devices. Sending the UNLISTEN commands the listening devices
 to get off the serial bus so it can be used for other purposes.
-<tag/Notes/<itemize>
-<item>
-</itemize>
 <tag/Availability/cc65
 <tag/See also/
 <ref id="cbm_k_listen" name="cbm_k_listen">
@@ -2353,6 +2354,28 @@ to get off the serial bus so it can be used for other purposes.
 </quote>
 
 
+<sect1>cbm_k_untlk<label id="cbm_k_untlk"><p>
+
+<quote>
+<descrip>
+<tag/Function/Send an UNTALK command
+<tag/Header/<tt/<ref id="cbm.h" name="cbm.h">/
+<tag/Declaration/<tt/void cbm_k_untlk (void);/
+<tag/Description/This function commands all devices on the serial bus to
+stop sending data to the host computer (i.e., UNTALK). Calling this
+function results in an UNTALK command being transmitted on the serial
+bus. Only devices previously commanded to TALK are affected. This
+function is normally used after the host computer is finished listening to data
+from an external device. Sending the UNTALK commands the sending devices
+to get off the serial bus so it can be used for other purposes.
+<tag/Availability/cc65
+<tag/See also/
+<ref id="cbm_k_talk" name="cbm_k_talk">
+<tag/Example/None.
+</descrip>
+</quote>
+
+
 <sect1>cclear<label id="cclear"><p>
 
 <quote>
@@ -5866,7 +5889,7 @@ if (rename (OLDNAME, NEWNAME) == 0) {
 before a call to <tt/set_brk/.
 <tag/Notes/<itemize>
 <item>The break vector is reset on program termination, so it's not strictly
-necessary to call this function as a part of your clean-up when exitting the program.
+necessary to call this function as a part of your clean-up when exiting the program.
 </itemize>
 <tag/Availability/cc65
 <tag/See also/
@@ -5888,7 +5911,7 @@ necessary to call this function as a part of your clean-up when exitting the pro
 <tag/Description/<tt/reset_irq/ resets the C level interrupt request vector.
 <tag/Notes/<itemize>
 <item>The interrupt vector is reset on program termination, so it's not strictly
-necessary to call this function as a part of your clean-up when exitting the program.
+necessary to call this function as a part of your clean-up when exiting the program.
 </itemize>
 <tag/Availability/cc65
 <tag/See also/
@@ -6249,7 +6272,7 @@ the continue with the interrupted code, you have to adjust <tt/brk_pc/,
 otherwise the <tt/BRK/ instruction will get executed over and over again.
 <item>The break vector is reset on program termination, so it's not strictly
 necessary to call <tt/<ref id="reset_brk" name="reset_brk">/ as a part of your
-clean-up when exitting the program.
+clean-up when exiting the program.
 </itemize>
 <tag/Availability/cc65
 <tag/See also/
@@ -6287,7 +6310,7 @@ enable stack checks for the handler function or any other function called from
 it.
 <item>The interrupt vector is reset on program termination, so it's not strictly
 necessary to call <tt/<ref id="reset_irq" name="reset_irq">/ as a part of your
-clean-up when exitting the program.
+clean-up when exiting the program.
 </itemize>
 <tag/Availability/cc65
 <tag/See also/