Software/Models This category references commercial and government software, essentially providing a clearinghouse of software. References are provided to hundreds of free software programs and models available for download off the Internet - see the EnviroSource Subject Guide titled Databases/Online Systems Guide for information about downloading software off the Internet. Please note that in many cases commercial providers will sell enhanced versions of government models. Related References Software systems that are specific to another EnviroSource category are referenced in the other category. This provides more specificity when browsing, i.e. references here do not fit better into other categories. Related resources such as databases and computer-based training are referenced in other more appropriate categories - see Databases and Training Providers. Definitions Software is defined in this category as an application useful for estimation, modeling, data management, processing, converting, calculation, etc.