  This is an abstract of authors PhD thesis which is devoted to studies of
quantum field models with strong coupling. The {\em Schwinger-Dyson equations}
(SDEs) in momentum representation are solved in Minkowski space. The original
version of the paper hep-ph/0108160 is included in. The full text of author's
PhD thesis can be found at this WWW:
'http://gemma.ujf.cas.cz/~sauli/papers.html'
