1. Bifurcation of zeroes of parametrized functions;Alexander, J. C.;J. Functional Analysis,1978
2. Global bifurcations of periodic orbits;Alexander, J. C.;Amer. J. Math.,1978
3. Calculating bifurcation invariants as elements in the homotopy of the general linear group;Alexander, J. C.;J. Pure Appl. Algebra,1978
4. Nontrivial solutions for a class of nonresonance problems and applications to nonlinear differential equations;Amann, H.;Ann. Scuola Norm. Sup. Pisa Cl. Sci. (4),1980
5. Multiple periodic solutions for a class of nonlinear autonomous wave equations;Amann, H.;Houston J. Math.,1981