The wikipedia page on plane quartics (http://en.m.wikipedia.org/wiki/Quartic_plane_curve) mentions the possible number of singularities that such a curve can have, including some examples. I'd like to have an explicit example of a quartic having precisely two ordinary double points, or, if possible, a parametrization of an entire family of such curves. Any explicit examples or references would be appreciated.
Background: I am interested in elliptic curves occuring as desingularizations, and such quartics should yield examples by the genus formula. (I started by considering singular Weierstrass equations, but their normalizations are rational)