2-Methylene analogs of 1alpha-hydroxy-19-norvitamin D3: synthesis, biological activities and docking to the ligand binding domain of the rat vitamin D receptor.
Grzywacz P, Plum LA, Sicinska W, Sicinski RR, Prahl JM, DeLuca HF, J Steroid Biochem Mol Biol, 2004 May - link

2-Ethyl and 2-ethylidene analogues of 1alpha,25-dihydroxy-19-norvitamin D(3): synthesis, conformational analysis, biological activities, and docking to the modeled rVDR ligand binding domain.
Sicinski RR, Rotkiewicz P, Kolinski A, Sicinska W, Prahl JM, Smith CM, DeLuca HF, J Med Chem, 2002 Aug 1 - link