TY  - BOOK
AU  - Casas,Willie
AU  - Zurbano,Joel E.
TI  - 2 variants blamed for upsurge
KW  - 2 variants
KW  - upsurge
UR  - http://elibrary.doh.gov.ph/cgi-bin/koha/opac-retrieve-file.pl?id=6935c60ff24c7cdd3abec163f74c4c1d
ER  -