^Uhlenbrock K, Gassenhuber H, Kostenis E (November 2002). "Sphingosine 1-phosphate is a ligand of the human gpr3, gpr6 and gpr12 family of constitutively active G protein-coupled receptors". Cellular Signalling. 14 (11): 941–953. doi:10.1016/S0898-6568(02)00041-4. PMID12220620.
Heiber M, Docherty JM, Shah G, Nguyen T, Cheng R, Heng HH, et al. (January 1995). "Isolation of three novel human genes encoding G protein-coupled receptors". DNA and Cell Biology. 14 (1): 25–35. doi:10.1089/dna.1995.14.25. PMID7832990.
"GPR6". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Archived from the original on 2012-09-02. Retrieved 2009-04-24.