https://link.springer.com/content/pdf/10.1007/BF01136085.pdf (Publisher version)
Apfelbach, R., & Weiler, E. (1991). Sensitivity to odors in wistar rats is reduced after low-level formaldehyde-gas exposure. Die Naturwissenschaften, 78(5), 221-223. doi:10.1007/BF01136085.pdf.