1. Bmdy. G. F. ii 965). Relarionshp be:ares matema) nit~tiadcs md khaviour. Joirrnii: of Psrscinili: arld Silcla; P~scii~;ic,g!,23 7 - 3 2 ?
2. Brunk. h f A, 6r Hsnggeier. S. \.i" (1954!. Chiid intIurnzrs 0 3 ad-lt contsois. An cxperimen!aI study De~el:~,nrt~r?iiii Ps>t,i~~i.?g?