Complex sentence: Some findings that Nikki Crick had concluded are as follows, forms of peer maltreatment that are common in boys'peer groups occur much less frequently in girls' peer groups and the conclusion that girls were more relationally victimized, whereas boys were more overtly victimized.
Split into simpler sentences: Some findings that Nikki Crick had concluded are as follows, forms of peer maltreatment that are common in boys'peer groups occur much less frequently in girls' peer groups. Another conclusion she had came upon is that girls were more relationally victimized, whereas boys were more overtly victimized.