Goh, DL; Lee, BW; Chia, KS; Heng, BH; Chen, M; Ma, S; Tan, CC; (2004) Secondary household transmission of SARS, Singapore. Emerging infectious diseases, 10 (2). pp. 232-4. ISSN 1080-6040 https://researchonline.lshtm.ac.uk/id/eprint/8667