TY - JOUR AU - M. M. Postnikov TI - Investigations in homotopy theory of continuous mappings. I.~The algebraic theory of systems. II.~The natural system and homotopy type JO - Informatics and Automation PY - 1955 SP - 3 EP - 158 VL - 46 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/TRSPY_1955_46_a0/ LA - ru ID - TRSPY_1955_46_a0 ER -