books.google.com.au - Rough-and-tumble play provided one of the paradigmatic examples of the appli- tion of ethological methods, back in the 1970's. Since then, a modest number of - searchers have developed our knowledge of this kind of activity, using a variety of methods, and addressing some quite fundamental questions...https://books.google.com.au/books/about/New_Aspects_of_Human_Ethology.html?id=S7JhYU479RUC&utm_source=gb-gplus-shareNew Aspects of Human Ethology
