This claim is a matter of everyday chemical observation and basic stoichiometry regarding acid-base neutralization and exothermic or byproduct formation; no specific paper citation is necessary.
The claim states a fundamental chemical principle that mixing certain safe or standard chemicals in neutralization reactions can yield hazardous compounds or unexpected byproducts. This is a basic piece of chemical knowledge grounded in the properties of reactive substances rather than a specialized empirical finding requiring a citation. Therefore, it is categorized as common knowledge.