by Ritchie, P M, Forbes, J C, Steinbok, P
Published in Canadian Medical Association journal (CMAJ) (01.07.1987)

by Burdge, D R, Woo, V C, Ritchie, P M
Published in Canadian journal of infectious diseases (01.01.1992)

by Burdge, D R, Woo, V C, Ritchie, P M
Published in The Canadian journal of infectious diseases = Journal canadien des maladies infectieuses (01.07.1992)

by Kerri Ritchie for PM
Published in ABC Premium News (22.01.2010)

by Kerri Ritchie for PM
Published in ABC Premium News (07.01.2010)

by Kerri Ritchie for PM
Published in ABC Premium News (06.11.2009)

by New Zealand correspondent Kerri Ritchie for PM
Published in ABC Premium News (25.01.2010)

by New Zealand correspondent Kerri Ritchie for PM
Published in ABC Premium News (11.12.2009)