diff --git a/doc/modbus_mapping_new.txt b/doc/modbus_mapping_new.txt
index 500619d..c9a31aa 100644
--- a/doc/modbus_mapping_new.txt
+++ b/doc/modbus_mapping_new.txt
@@ -32,7 +32,7 @@ successful. Otherwise it shall return NULL and set errno.
 
 ERRORS
 ------
-ENOMEM::
+*ENOMEM*::
 Not enough memory
 
 
diff --git a/doc/modbus_read_bits.txt b/doc/modbus_read_bits.txt
index dc81137..a9ecead 100644
--- a/doc/modbus_read_bits.txt
+++ b/doc/modbus_read_bits.txt
@@ -32,7 +32,7 @@ successful. Otherwise it shall return -1 and set errno.
 
 ERRORS
 ------
-EMBMDATA::
+*EMBMDATA*::
 Too many bits requested
 
 
diff --git a/doc/modbus_read_input_bits.txt b/doc/modbus_read_input_bits.txt
index 5d54078..51f53fa 100644
--- a/doc/modbus_read_input_bits.txt
+++ b/doc/modbus_read_input_bits.txt
@@ -32,7 +32,7 @@ input status if successful. Otherwise it shall return -1 and set errno.
 
 ERRORS
 ------
-EMBMDATA::
+*EMBMDATA*::
 Too many discrete inputs requested
 
 
diff --git a/doc/modbus_read_input_registers.txt b/doc/modbus_read_input_registers.txt
index 1942276..253b767 100644
--- a/doc/modbus_read_input_registers.txt
+++ b/doc/modbus_read_input_registers.txt
@@ -34,7 +34,7 @@ input registers if successful. Otherwise it shall return -1 and set errno.
 
 ERRORS
 ------
-EMBMDATA::
+*EMBMDATA*::
 Too many bits requested
 
 
diff --git a/doc/modbus_read_registers.txt b/doc/modbus_read_registers.txt
index 509971f..2f6378d 100644
--- a/doc/modbus_read_registers.txt
+++ b/doc/modbus_read_registers.txt
@@ -32,7 +32,7 @@ if successful. Otherwise it shall return -1 and set errno.
 
 ERRORS
 ------
-EMBMDATA::
+*EMBMDATA*::
 Too many registers requested
 
 
diff --git a/doc/modbus_reply.txt b/doc/modbus_reply.txt
index 142e13b..93503e4 100644
--- a/doc/modbus_reply.txt
+++ b/doc/modbus_reply.txt
@@ -33,7 +33,7 @@ successful. Otherwise it shall return -1 and set errno.
 
 ERRORS
 ------
-EMBMDATA::
+*EMBMDATA*::
 Sending has failed
 
 See also the errors returned by the syscall used to send the response (eg. send
diff --git a/doc/modbus_write_and_read_registers.txt b/doc/modbus_write_and_read_registers.txt
index 0bbcd66..91fd14c 100644
--- a/doc/modbus_write_and_read_registers.txt
+++ b/doc/modbus_write_and_read_registers.txt
@@ -34,7 +34,7 @@ registers if successful. Otherwise it shall return -1 and set errno.
 
 ERRORS
 ------
-EMBMDATA::
+*EMBMDATA*::
 Too many registers requested, Too many registers to write
 
 
diff --git a/doc/modbus_write_bits.txt b/doc/modbus_write_bits.txt
index aca55c3..071a0b0 100644
--- a/doc/modbus_write_bits.txt
+++ b/doc/modbus_write_bits.txt
@@ -29,7 +29,7 @@ successful. Otherwise it shall return -1 and set errno.
 
 ERRORS
 ------
-EMBMDATA::
+*EMBMDATA*::
 Writing too many bits