@article{Lehenkyi_2004 author = {Victor I. Lehenkyi}, title = {Theoretic-Group Criterion for Reduction of the Equation G(t, x, x',...) + εF(t, x, x',...)= 0 to the Form G(t^, x^, x^´,...) = 0}, journal = {Journal of Automation and Information Sciences}, issn = {1064-2315}, year = {2004}, volume = {36}, number = {4}, pages = {18--25} }