In his new book:
jean-claude Perez presents in details his discovery of a predictive formula of the PERIODIC LAW only based on period "p" and number "2"...
see also this other website on Mendeleiev's law...(laetusinpraesens.org)
se also in Belgrade University web site: http://www.mi.sanu.ac.rs/vismath/perez2009/perez.pdf
http://www.mi.sanu.ac.rs/vismath/perez2009/perez.pdf