In a daily time-place learning task, time is only used as a discriminative stimulus if each daily session is associated with a distinct spatial location
Learning & Behavior (2014) - Comment
pubmed: 24906889  doi: 10.3758/s13420-014-0142-1  issn: 1543-4508  issn: 1543-4494 

Scott H. Deibel, Matthew L. Ingram, Andrew B. Lehr, Hiliary C. Martin, Darlene M. Skinner, Gerard M. Martin, Isaac M. W. Hughes, Christina M. Thorpe