Ms. Volkov et al., THE NUMBER OF SPHALERON INSTABILITIES OF THE BARTNIK-MCKINNON SOLITONS AND NON-ABELIAN BLACK-HOLES, Physics letters. Section B, 349(4), 1995, pp. 438-442
It is proven that there are precisely n odd-parity sphaleron-like unst
able modes of the n-th Bartnik-McKinnon soliton and the n-th non-abeli
an black hole solution of the Einstein-Yang-Mills theory for the gauge
group SU(2).