The most important historical reference on the Kadiwéu (or the Guaikurú-Mbayá) is found in the work of F. José Sanchez-Labrador, entitled El Paraguay Católico, considered one of the best ethnographies written in the 18th century. Various 19th century chroniclers recorded, in greater or lesser detail, their impressions of these Indians, their localization, way of life and relations with the colonizers. Standing out among them are Ricardo Franco de Almeida Serra, Francisco Rodrigues do Prado, Alexandre Rodrigues Ferreira, Francis Castelnau, Alfred d'Escragnole Taunay (who narrated episodes concerning the indigenous participation in the Paraguayan War) and, most notably, Guido Boggiani. The last author lived for several months among the Kadiwéu at the end of the 19th century and amid other writings left us his rich field diary relating to the visit, published as Os Caduveos. Boggiani collected a vast amount of material representing Kadiwéu art and artefacts, whose most important collection is found today conserved by the Luigi Pigorini Museum, in Rome. Historical information can also be derived from the reports of Presidents of the Province of Mato Grosso, kept by the National Archive. As for anthropological works properly speaking, Alfred Métraux provides us with ethnological studies on the Indians of the Grand Chaco, especially on those aspects concerning religion. Claude Lévi-Strauss stayed among the Kadiwéu in 1937 and wrote about their art. Darcy Ribeiro pursued field research among the Kadiwéu at the end of the 1940s and his most important works on the group are collected in the volume Kadiwéu: Ensaios Etnológicos sobre o Saber, o Azar e a Beleza, which, as the title indicates, deals with mythology, shamanism and art. He also wrote an article: 'O sistema familial Kadiwéu' (1948). More recently, two M.Phil. theses have been written on the people: the thesis by Jaime Siqueira Jr. (USP, 1993) studies the construction of Kadiwéu time and space; Mônica Thereza Pechincha's thesis is entitled Histórias de Admirar: Mito, Rito e História Kadiwéu (UnB, 1994). The Kadiwéu language has been studied by Silvia L.B. Braggio (1981). As for technical reports, it is worth mentioning those produced by Alain Moreau, who has frequented and accompanied Kadiwéu society for a number of years and through his own initiative has provided them with valuable juridical support, especially in effecting the process of substituting the farm tenancy system.