A review of the experimental work performed at the GASP array with the purpose of the identification and first spectroscopic measurements of the heaviest even--even N=Z and odd-A N=Z+1 nuclei (mass larger than 80) is made. Systematic experiments in this mass region led to the first study of seven such nuclei: ⁸⁸Ru, ⁸¹Zr, ⁸⁵Mo, ⁸⁹Ru, ⁹¹Rh, ⁹³Pd, and ⁹⁵Ag, and extensive data on many other nuclei in their neighborhood. The systematic evolution of the level structures in both even--even and odd-A nuclei, between N \approx Z \approx 40 and N \approx Z \approx 47 is briefly presented. The possibility that effects of the neutron--proton pairing have been observed, as well as the type of collectivity observed in this region are discussed.

PACS numbers: 21.10.--k, 21.60.--n, 23.20.--g