The physical explanation of static electric shocks resulting from contact electrification and subsequent discharge is a matter of everyday observation and textbook physics, requiring no formal citation.
The claim states that static electric shocks from door handles are caused by triboelectric charging and sudden discharge. This is a fundamental, well-known physical phenomenon (contact electrification and electrostatic discharge) that is trivially true by basic everyday observation and foundational physics principles. Per instructions, claims that are trivially true by everyday observation are classified as COMMON_KNOWLEDGE, do not require citations, and have empty index lists.