Financing is another practical difficulty for the directory projects. As with many important green economic areas (e.g. energy conservation), there is (as yet) no powerful financial interest group to support eco-materials development and education. These initiatives usually employ a mix of government grants, membership customer subscriptions, and corporate sponsorship. The Environmental Building Newss Green Spec guide (accessible at http://www.buildinggreen.com/) makes no money from industry sources since it wants its guide to have complete credibility as a source of ecological information. As of February 2005, it was charging US$12.95 for one-week on-line access to the directory; US$199 for one-year electronic access (including a subscription to the Environmental Building News monthly newsletter); and was selling a hard-cover version for US$89. Green Spec has detailed listings for more than 1,850 green building products with environmental data, manufacturer information, and links to additional resources. The Austin Green Builder Sourcebook (accessible at http://www.greenbuilder.com/sourcebook/) does accept corporate sponsorship for chapters of its guide. It tastefully lists the sponsors on its website directory, but does not have ads. The Sourcebook is a well-respected information source in the green building community throughout the US, and the acceptance of corporate sponsorship does not seem to have affected its critical standpoint. The Montana-based CRBTs guide (accessible at http://www.crbt.org/) is funded by the US Brown Foundation. Its foundation funding is quite typical of the way many of the free online directories are funded. Other projects combine corporate contributions, government and foundation funding, and customer fees.