exp.at exp.at ’19 : Online experimentation. 5th Experiment@ international conference. Funchal, Portugal. June 12-14, 2019. -- Danvers : IEEE, 2019. -- ISBN : 978-1-7281-3637-0. -- 978-1-7281-3636-3 (USB). -- CFP19EXP-ART. Cardoso, Alberto. Restivo, Maria Teresa. Augusto Sousa. Gomes, Abel