Some simple ada-sources, done for the University of Stuttgart.
You can find the GNU Ada compiler GNAT at the GeekGadgets ftp-site:

http://www.ninemoons.com

Literature:

Programming in Ada95, 2nd edition
(also known as 'The Barnes Bible')
John Barnes
Addison-Wesley
ISBN 0-201-34293-6

Ada from the beginning
Jan Skansholm
Addison-Wesley
ISBN 0-201-17522-3

 PERMSSN    UID  GID    PACKED    SIZE  RATIO     CRC       STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                  592    1233  48.0% -lh5- c385 Mar  1  2001 Ada_src2/AUFG12.info
[generic]                  289     588  49.1% -lh5- 5e1e Jan 26  2001 Ada_src2/AUFG12/LISTS.ADB
[generic]                 4095    5625  72.8% -lh5- 84a1 Feb 21  2001 Ada_src2/AUFG12/LISTS.ADB.info
[generic]                  271     542  50.0% -lh5- d947 Jan 26  2001 Ada_src2/AUFG12/LISTS.ADS
[generic]                 4098    5625  72.9% -lh5- abd5 Feb 21  2001 Ada_src2/AUFG12/LISTS.ADS.info
[generic]                  124     203  61.1% -lh5- 29e9 Jan 26  2001 Ada_src2/AUFG12/LISTTEST.ADB
[generic]                 4097    5625  72.8% -lh5- d135 Feb 21  2001 Ada_src2/AUFG12/LISTTEST.ADB.info
[generic]                 1135    4187  27.1% -lh5- 28c0 Feb  7  2001 Ada_src2/AUFG12/SETS.ADB
[generic]                 4073    5604  72.7% -lh5- 73a6 Feb 21  2001 Ada_src2/AUFG12/SETS.ADB.info
[generic]                  531    1413  37.6% -lh5- 27d5 Feb  6  2001 Ada_src2/AUFG12/SETS.ADS
[generic]                 4074    5604  72.7% -lh5- 3f58 Feb 21  2001 Ada_src2/AUFG12/SETS.ADS.info
[generic]                  400     937  42.7% -lh5- 029c Feb  6  2001 Ada_src2/AUFG12/SETTEST.ADB
[generic]                 4071    5604  72.6% -lh5- 5e35 Feb 21  2001 Ada_src2/AUFG12/SETTEST.ADB.info
[generic]                  910    1970  46.2% -lh5- b77b Jan 15  2001 Ada_src2/xmastree.adb
[generic]                 4094    5625  72.8% -lh5- cc71 Mar  1  2001 Ada_src2/xmastree.adb.info
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total        15 files   32854   50385  65.2%            Mar  3  2001