mentioned by trauma on call plan specification collection of trauma service surgeons reviewed by the TMD A collection of surgeons whose members are mentioned in a trauma on call plan specification and that are subject to a performance review by the trauma medical director. Initially, we used the SubClass restriction, with 'only' after 'is aggregate of' as an equivalent to restriction, which fully defines this set. However, given the number of collections in OOSTT this negatively affected reasoning time. For our data management purposes having the restriction as an existential restriction is totally sufficient, so we go with this. Mathias Brochhausen Sarah Bost collection of surgeons