Comparison of current chemical and stereochemical tests for the identification and differentiation of Pelargonium oils: Analytical data for (-)-(1S, 4R, 5S)-guaia-6,9-diene and (-)-(7R,10S)-10-EPI-γ-eudesmol - Wang, M; Chittiboyina, AG; Avonto, C; Parcher, JF; Khan, IA (Planta Medica, 2014)