TaxJar - TaxJar simplifies sales tax filing for eCommerce sellers.
Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.
Thomson Reuters ONESOURCE - ONESOURCE tax software and solutions synchronize every aspect of your work and link international, country, state and local tax laws.
Tax990 - Tax 990 is an IRS-authorized e-filing solution for nonprofit organizations that helps clients understand the process of filing 990 series returns.
Octobat - Octobat provides automated tax-compliance and accounting for digital businesses.
Qiqqa - Qiqqa is a free research and reference management software. It can be used in many organizational projects from the academic to the personal to the business endeavor. Read more about Qiqqa.