Stability and hyperfine structure of the four- and five-body muon-atomic clusters a+b+μ−e− and a+b+μ−e−e− A.M. Frolov and D.M. Wardlaw Eur. Phys. J. D, 66 5 (2012) 132 Published online: 23 May 2012 DOI: 10.1140/epjd/e2012-30076-6