[http://books.google.com.co/books?id=cnWlF6H89PQC&printsec=frontcover&dq=william+zikmund+investigacion+de+mercados&hl=es&sa=X&ei=dKGgT-X0BoWE8QSf6pWoCA&ved=0CC8Q6AEwAA#v=onepage&q=william%20zikmund%20investigacion%20de%20mercados&f=false%20*%5Bhttp://www.marketing-xxi.com/capitulo-3-la-investigacion-de-mercados.html%20Capítulo%20sobre%20Estudios%20de%20Mercado%5D%20del%20libro%20"Marketing%20en%20el%20Siglo%20XXI".