MODELOS DE CAPAS SHELL MODELS A graphical procedure to evaluate the many-body shell-model equations ELEMENTOS DE MATRIZ ESTADOS FUNDAMENTALES ESTADOS YRAST EVEN-ODD NUCLEI|NUCLEOS PAR-IMPAR FUNCIONES DE ONDA GROUND STATES MATRIX ELEMENTS Microscopic description of yrast states in spherical nuclei PARTICLES PARTICULAS Structure of Single-Particle States in Spherical Nuclei within the Framework of the Multistep Shell-Model Method VECTORES VECTORS WAVE FUNCTIONS YRAST STATES