How to find out who funded a study / research? It has been proven that the source of funding can have an influence on the results of a research (funding bias, well documented here and here).

When we check for pieces of research, for example through the Pubmed database, how can we check the source of funding? (And check for possible financial conflict of interest?)
Reputable journals might require authors to disclose funding sources, but as noted, this practice, reputable journals notwithstanding, is inconsistent.  Beyond this, there are no standards for determining what is a reputable journal.  

As to the comment that two citations do not prove the point, the literature is replete with studies demonstrating funding bias; a few examples: Pharmaceutical industry sponsorship and research outcome and quality, Lexchen, Bern et al; Avoiding biasing the conduct and reporting…, Hillman, Eisenberg, et al; Systematic review of empirical evidence of study publication bias, Dwan, Altman et al.