Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Steve Collins and Andy Ruina and Russ Tedrake and Martijn Wisse,Efficient Bipedal Robots Based on Passive-Dynamic Walkers,Science,0036-8075,American Association for the Advancement of Science (AAAS),2005-02-18,307,5712,1082-1085,https://cir.nii.ac.jp/crid/1363107371033647744,https://doi.org/10.1126/science.1107799