fix various typos across all manuals
diff --git a/doc/manuals/chapters/gsup.adoc b/doc/manuals/chapters/gsup.adoc
index 9efc8c0..838af7d 100644
--- a/doc/manuals/chapters/gsup.adoc
+++ b/doc/manuals/chapters/gsup.adoc
@@ -29,14 +29,14 @@
* IPA OSMO protocol extension: 0x05
For more information about the IPA multiplex, please see the 'OsmoBTS
-Abis/IP Specifiation'.
+Abis/IP Specification'.
=== Procedures
==== Authentication management
The SGSN sends a SEND_AUTHENTICATION_INFO_REQ message containing the MS's IMSI
-to the peer. On errors, especially if authentication info is not availabe for
+to the peer. On errors, especially if authentication info is not available for
that IMSI, the peer returns a SEND_AUTHENTICATION_INFO_ERR message. Otherwise
the peer returns a SEND_AUTHENTICATION_INFO_RES message. If this message
contains at least one authentication tuple, the SGSN replaces all tuples that