I present a toolkit for tracing information flows in nineteenth-century newspapers by identifying sources, intermediaries, and authors across multiple digitised collections. Motivated by rumours such as the “Great Moon Hoax,” the methods generalise to broader questions about how news and scientific claims circulated across national and linguistic borders. The toolkit combines three elements: (1) a cross-collection gazetteer of historical newspaper titles; (2) detection of explicit sourcing and implicit text reuse; and (3) an inspectable network view of inferred flows. I build a title authority list by harmonising catalogues from impresso, Chronicling America, and British Library/British Newspaper Archive sources, normalising title variants and resolving duplicates via fuzzy matching and shared metadata. The gazetteer anchors short, ambiguous references (e.g., “according to the Herald”) to concrete newspapers even when titles appear in variant or OCR-degraded forms. For explicit sourcing and signatures, I combine cue patterns (including multilingual equivalents), lightweight named-entity recognition, and positional/formatting heuristics. For implicit transmission, I compute n-gram similarity over candidate article pairs and use publication dates to propose directionality. Relations are stored in a graph model and explored through notebook-based filtering and path inspection, supporting historical questions about media geography, multilingual circulation, and the politics of reprinting.