Enrico Valdinoci Plane-like minimizers in periodic media: jet flows and Ginzburg-Landau (725K, PostScript) ABSTRACT. This dissertation will consider Ginzburg-Landau functional with integer peiodicity. We will show the existence of ``plane-like'' quasi-periodic minimizers. As a limiting case, we re-obtain the recent result by Caffarelli and de la Llave.