Use of Polar Heliostats to Improve Levels of Natural Lighting inside Buildings with Little Access to Sunlight. - Luis Manuel Fernández-Ahumada; Maximiliano Osuna-Mérida; Jesús López-Sánchez; Francisco Javier Gómez-Uceda; Rafael López-Luque; Marta Varo Martínez (Sensors, 2022)