Search for "spiro[indoline-3,4'-pyridine]" in Full Text gives 2 result(s) in Beilstein Journal of Organic Chemistry.
Beilstein J. Org. Chem. 2014, 10, 2671–2676, doi:10.3762/bjoc.10.281
Beilstein J. Org. Chem. 2013, 9, 846–851, doi:10.3762/bjoc.9.97