Published in Gardens' Bulletin Singapore, in 1989, in volume 42, issue 1, pages 1-17

Published in Gardens' Bulletin Singapore, in 1989, in volume 42, issue 1, pages 19-24

Published in Gardens' Bulletin Singapore, in 1989, in volume 42, issue 1, pages 25-28

Published in Gardens' Bulletin Singapore, in 1989, in volume 42, issue 1, pages 29-44

Published in Gardens' Bulletin Singapore, in 1989, in volume 42, issue 1, pages 47-64

Published in Gardens' Bulletin Singapore, in 1989, in volume 42, issue 1, pages 65-69

Published in Gardens' Bulletin Singapore, in 1989, in volume 42, issue 1, pages 71-73

Published in Gardens' Bulletin Singapore, in 1989, in volume 42, issue 1, pages 75-77