New Symmetric (61,16,4) Designs Invariant Under the Dihedral Group of Order 10

∗ This work has been partially supported by the Bulgarian NSF under Contract No. I-506/1995.

Structure of the Unit Group of FD10

2000 Mathematics Subject Classification: 16U60, 20C05.

On realizability of p-groups as Galois groups

2000 Mathematics Subject Classification: 12F12, 15A66.