Ungson, R. (1975). Abaca marketing, Part I: Bicol. Special Studies Division, Dept. of Agriculture.
Lua i Stíl Chicago (17ú heag.)Ungson, R.D. Abaca Marketing, Part I: Bicol. Quezon City: Special Studies Division, Dept. of Agriculture, 1975.
Lua MLA (9ú heag.)Ungson, R.D. Abaca Marketing, Part I: Bicol. Special Studies Division, Dept. of Agriculture, 1975.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.