Evgeni Tsivtsivadze Tapio Pahikkala Jorma Boberg Tapio Salakoski Locality kernels for sequential data and their applications to parse ranking. 81-88 2009 31 Appl. Intell. 1 http://dx.doi.org/10.1007/s10489-008-0114-2 db/journals/apin/apin31.html#TsivtsivadzePBS09