Le Play's work was further developed by his many disciples: Adolphe Focillon (1823-1890), Émile Cheysson (1836-1910), Alexis Delaire (1836-1915), Henri de Tourville (1842-1903), Claudio Jannet (1844-1894), Edmond Demolins (1852-1907), Paul de Rousiers (1857-1934), Gabriel Olphe-Galliard (1870-1947), the Belgian Victor Brants (1854-1917) and the Canadian Léon Gérin. After an eclipse between the 1940s and the 1960s Le Play's methods resurfaced when the "history of the family" became a new field of interest in social science. In Britain, Peter Laslett who worked within the Cambridge Group for the History of Population and Social Structure used le Play's methods at the end of the 1960s to study family structures from census and property transmission data, describing particularly the nuclear family structure which Le Play had not worked on. At about the same time in France, legal history academics working on customary law were the first to re-apply Le Play's methods in scientific research. In the early 1970s, a growing number of ethnologists and historians joined this trend, especially those within the historical anthropology school: André Burguière, Emmanuel Le Roy Ladurie. In a 1989 book which became a reference in its field, ethnologist Georges Augustins reshaped Le Play's family types classification. Some sociologists rediscovered Le Play's work as well from the late 1960s on, overcoming the general opinion that Le Play's views were just overly conservative, particularly Paul Lazarsfeld, Antoine Savoye and Bernard Kalaora. At the end of the 1970s historian and demographer Emmanuel Todd, a disciple of both Emmanuel Le Roy Ladurie and Peter Laslett, was struck by the geographical similarity between the area of prevalence of the communitarian family system (patriarcal family in Le Play's words) and the regions where communism had become dominant in the 20th century. He reprocessed Le Play's study of family structures and published a number of widely publicised books establishing a link between traditional family structures and the great ideological and society movements in European history (religious and political choices, economic development, ...). Works (1843) "Sur la Fabrication de l’ Acier en Yorkshire" Annale des Mines, 4e série, Tome III, pp. 195ff. (bound with the following:) (1846) Mémoire sur la fabrication, le commerce et l'emploi des fers à acier du Nord de l'Europe. (1864). La Réforme Sociale. (1871). L'Organisation de la Famille. (1875). La Constitution de l'Angleterre. (in collaboration with M. Delaire) In English translation (1872). The Organization of Labor in Accordance With Custom and the Law