Ultra-Bright and -Stable Red and Near-Infrared Squaraine Fluorophores for In Vivo Two-Photon Imaging Podgorski, Kaspar ; Terpetschnig, Ewald ; Klochko, Oleksii P. ; Obukhova, Olena M. ; Haas, Kurt Abstract Publication: PLoS ONE Pub Date: December 2012 DOI: 10.1371/journal.pone.0051980 Bibcode: 2012PLoSO...751980P