http://books.google.pt/books?id=z0qdRiK7I_gC&lpg=PP1&hl=pt-PT&pg=PP1#v=onepage&q&f=true

http://books.google.pt/books?id=YUtYBAAAQBAJ&printsec=frontcover&hl=pt-PT&output=html_text

http://mitran-lab.amath.unc.edu/courses/MATH768/biblio/introduction-to-prob-models-11th-edition.PDF

https://faculty.ksu.edu.sa/sites/default/files/an_introd_to_stoch_modeling_4th_ed.pdf