1U. S. NRC. Valuing Ground Water.National Academy Press[].Internet.1997
2Bransford,J.,Stevens,R.,Schwartz,D.,Meltzoff,A.,Pea,R.,Roschelle,J.,Vye,N.,Kuhl,P.,Bell,P.,Barron,B.,Reeves,B.,Sabelli,N.,Alexander Winne,P. A. P. H.Learning theories and education: Toward a decade of synergy[].Handbook of educational psychology Second edition.2006