Trial of calcium for preeclampsia prevention (CPEP): Rationale, design, and methodsRichard J. Levine; Joy R. Esterlitz; Elizabeth G. Raymond; Rebecca DerSimonian; John C. Hauth; L.Ben Curet; Baha M. Sibai; Patrick M. Catalano; Cynthia D. Morris; John D. Clemens; Marian G. Ewell; Steven A. Friedman; Robert L. Goldenberg; Sig-Linda Jacobson; Gary M. Joffe; Mark A. Klebanoff; Alice S. Petrulis; Jose G. Rigau-Perez · 1996