1. Solutions of the collinear four-body problem which become unbounded in finite time;Mather,1974
2. Solutions of the collinear four-body problem which become unbounded in finite time;Mather,1975
3. Leçons sur la théorie analytique des équations différentielles;Painlevě,1897
4. Singularities and collisions of Newtonian gravitational systems;Saari;Arch. Rational Mech. Anal.,1972
5. A global existence theorem for the four body problem;Saari;J. Differential Equations,1977