^Wu, Y.-H., Rayburn, J. W., Allen, L. E., Ferguson, H. C., & Kissel, J. W. (1972). Psychosedative agents. 2. 8-(4-Substituted 1-piperazinylalkyl)-8-azaspiro[4.5]decane-7,9-diones. Journal of Medicinal Chemistry, 15(5), 477–479.
^Comoy C, Benarab A, Leinot M, Monteil A, Guillaumet G. Synthesis of various analog derivatives of ORG13514 as 5-HT1A ligands. Farmaco. 1999 Nov-Dec;54(11-12):791-9. doi: 10.1016/s0014-827x(99)00106-8. PMID 10668181.
^Michael Konkel, et al. WO2000004012 (to H Lundbeck AS).