We present one of the first university books in physics written in the beginning of the XX century. The topic concerns a book written by Professor Đorđe Stanojević entitled Централне силе у Приподи (Central Forces in Nature) which was printed in 1906 in Belgrade. The book has been digitised and it is available through the Virtual Library of the National Digitisation Centre (Virtual Library, http://elibrary.matf.bg.ac.rs/).