Analysis of The Relationship Between Characteristics and Hardness of Strip Packing Problem Instances. - Edgar Alberto Oviedo Salas; Jesús David Terán Villanueva; Salvador Ibarra-Martínez; José Antonio Castán Rocha; Mirna Patricia Ponce Flores; Julio Laria-Menchaca; Mayra Guadalupe Treviño Berrones (Int. J. Comb. Optim. Probl. Informatics, 2021)