Date: Fri, 20 Dec 2002 From: Ruben Mkrtchyan Dear Predrag, Thank you for information on your group theory book. It is interesting for me, just now I would like to correct the reference on my article in Phys.Lett, (Ref [114]). It should be (last name is corrected and SO(-2n) instead of SO(2n)): R.L.Mkrtchyan, Equivalence of Sp(2n) and SO(-2n) gauge theories. Phys.Lett. 105B (1981) 174 Ruben Mkrtchyan, Yerevan Physics Institute, Alikhanian Br. Str.2, 375036, Yerevan, Armenia. E-mail: mrl@r.am Fax: (+3741)-569992 Tel: (+3749)-406354