That stabilized ylides yield trans (E) alkenes in the Wittig reaction is a standard textbook chemical principle, corroborated by general organic chemistry literature.
The claim is a well-established textbook fact regarding the stereochemical outcome of the Wittig reaction (stabilized ylides give predominantly E/trans-alkenes, whereas non-stabilized ylides give Z-alkenes). While it is foundational chemical knowledge, multiple retrieved papers touch upon Wittig stereoselectivity or E/Z control. Therefore, COMMON_KNOWLEDGE is appropriate, with supportive papers correctly indexed.