PubMed®	(infant* OR newborn OR baby* OR neonate) AND (movement OR “spontaneous movements”) AND (nonlinear* OR “non-linear” OR entropy OR Lyapunov OR “complexity” OR “time series”) NOT (EEG OR heart)
Institute of Electrical and Electronics Engineers®	(infant* OR newborn OR baby* OR neonate) AND (movement) AND (nonlinear OR “non-linear” OR entropy OR “time series” OR Lyapunov OR complexity) NOT (EEG OR heart)
Web of Science™	(Infant* OR newborn OR baby OR neonate) AND (movement OR “spontaneous movements”) AND (nonlinear OR “non-linear” OR entropy OR “time series” OR Lyapunov OR complexity) NOT (EEG OR heart)
ScienceDirect®	(infants OR newborn) AND (“general movements” OR “spontaneous movements”) AND (nonlinear OR “non-linear” OR entropy OR “time series”) NOT (heart)
Google Scholar	(infant* OR newborn OR baby OR neonate) AND (“spontaneous movements” OR “general movements”) AND (“non-linear” OR nonlinear OR entropy OR “time series” OR Lyapunov) -cardiac -heart -EEG