Sota, A.; Gorosabel, J.; Jelinek, M.
GRB Coordinates Network, Circular Service, 11928, 1 (2011)
"We have observed the XRT error circle (Goad et al. GCNC 11920) of GRB 110411A (Grupe et al. GCNC 11918) with the 1.5m telescope of Observatorio de Sierra Nevada, Granada, Spain.
The observations were carried out on April 2.06606-12.12741 UT (6.01-7.49 hours post trigger) in the R and I bands with an exposure time of 8x300s in each band. No object is detected within the XRT error circle down to R < 23.5 and I < 22.4, calibrated against USNO B1.0".