2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/153864This paper continues the series begun with works solv-int/9701016, solv-int/9702004 and solv-int/9703010. Here we construct more sophisticated strings, combining ideas from those papers and some considerations involving solutions of tetrahedron equation due to Sergeev, Mangazeev and Stroganov.LaTeX, 6 pagesExactly Solvable and Integrable Systemstext