[1] Inst Politecn Nacl, Escuela Super Fis & Matemat, Dept Matemat, Unidad Zacatenco, Mexico City, Mexico
[2] Inst Politecn Nacl, Escuela Super Ingn Mecan & Electr, Dept Ingenieria Comunicac & Elect, Unidad Zacatenco, Mexico City, Mexico
[3] Univ Autonoma Ciudad Mexico, Acad Matemat, Mexico City, Mexico
[4] Mangalore Univ, Constituent Coll, Field Marshal KM Cariappa Coll, Dept Math, Madikeri 571201, India
[5] JSS Sci & Technol Univ, Sri Jayachamarajendra Coll Engn, Dept Math, Mysuru 570006, India