@book{Troeltsch, author = {Troeltsch, E.}, title = {The social teaching of the christian churches. Vol. 1, New York (Harper \& Brothers) 1960.}, language = {en} } @book{Troeltsch, author = {Troeltsch, E.}, title = {The social teaching of the christian churches.Vol. 2, New York (Harper \& Brothers) 1960.}, language = {en} }