journals.cambridge.org .nature.com .opticsinfobase.org .symposium-journals.co.uk .journals.uchicago.edu .symposium-journals.co.uk .royalsocietypublishing.org .aps.org .tesisenred.net .loc.gov .lamjol.info .aip.org .blackwell-synergy.com .euppublishing.com .ingentaconnect.com .liebertonline.com .lyellcollection.org .palgrave-journals.com .rsc.org .scirus.com agris.fao.org asae.frymulti.com highwire.stanford.edu journals.pepublishing.com online.sagepub.com .ncbi.nlm.nih.gov static.pubmed.gov .ebrary.com .ebscohost.com .ebsco-content.com springerlink.com .scielo.org .scielo.br