Terhikki Manninen Lauri Korhonen Pekka Voipio Panu Lahtinen Pauline Stenberg Airborne Estimation of Boreal Forest LAI in Winter Conditions: A Test Using Summer and Winter Ground Truth. 68-74 2012 50 IEEE T. Geoscience and Remote Sensing 1 http://dx.doi.org/10.1109/TGRS.2011.2173939 db/journals/tgrs/tgrs50.html#ManninenKVLS12