High-spin states in doubly odd nuclei of 124Cs, 126Cs and 124La have b
een investigated by gamma ray spectroscopy. Rotational bands of pih11/
2 x nuh11/2 configuration have been assigned by the blocking argument
on the first band crossing frequencies for neighboring odd-A nuclei. I
n cesium isotopes, the signature inversion of quasiparticle routhians
has been observed. The spin of the band head in 124Cs has been determi
ned to be (7+) by means of spectroscopic method. This spin assignment
implies that the signature inversion occurs at low spin. The signature
dependence becomes normal at higher spins than 17hBAR. The occurrence
of the signature inversion in the A approximately 130 mass region is
discussed by comparing excitation energies, transition intensities and
the shell-model orbits of valence nucleons with those of rare-earth n
uclei.