Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Charalampos Bogdanos and Salvatore Capozziello and Mariafelicia De Laurentis and Savvas Nesseris,"Massive, massless and ghost modes of gravitational waves from higher-order gravity",Astroparticle Physics,0927-6505,Elsevier BV,2010-11,34,4,236-244,https://cir.nii.ac.jp/crid/1360855571211351424,https://doi.org/10.1016/j.astropartphys.2010.08.001