Thirty years later, Jean Liedloff caused a stir by a "Continuum concept" that she presented to the public in a book of the same title (1975). In Venezuela, Liedhoff had studied Ye'kuana people, and later she recommended to Western mothers to nurse and to wear their infants and to share their bed with them. She argued that infants, speaking in terms of evolution, have not arrived in the modernity yet, so that today's way of child care – with bottle feeding, use of cribs and baby carriages, etc. – does not meet their needs.[3] Later, authors such as Sharon Heller and Meredith Small contributed further ethnopediatric insights.[4]