Comparison of δ13C analyses of individual foraminifer (Orbulina universa) shells by secondary ion mass spectrometry and gas source mass spectrometry - Wycech, Jody; Kelly, Daniel; Kozdon, Reinhard; Ishida, Akizumi; Kitajima, Kouki; Spero, Howard; Valley, John (Rapid Communications in Mass Spectrometry, 2024)