Belarus, Canada, Morocco, and Tunisia. The convention is open for signature by other non-European states. It does not claim to create a universal model of anti-doping, but sets a certain number of common standards and regulations requiring parties to adopt legislative, financial, technical, educational and other measures. In this sense the Convention strives for the same general aims as WADA, without being directly linked to it. The main objective of the convention is to promote the national and international harmonization of the measures to be taken against doping. Furthermore, the Convention describes the mission of the monitoring group set up in order to monitor its implementation and periodically re-examine the list of prohibited substances and methods which can be found in an annex to the main text. An additional protocol to the Convention entered into force on 1 April 2004 with the aim of ensuring the mutual recognition of anti-doping controls and of reinforcing the implementation of the Convention using a binding control system. UNESCO International Convention Against Doping in Sport Given that many governments cannot be legally bound by a non-governmental document such as the World Anti-Doping Code, they are implementing it by individually ratifying the UNESCO International Convention against Doping in Sport, the first global international treaty against doping in sport, which was unanimously adopted by 191 governments at the UNESCO General Conference in October 2005 and came into force in February 2007. As of April 2020, 189 states had ratified the convention, setting a UNESCO record in terms of speed. The UNESCO Convention is a practical and legally binding tool enabling governments to align domestic policy with the World Anti-Doping Code, thus harmonizing the rules governing anti-doping in sport. It formalizes governments' commitment to the fight against doping in sport, including by facilitating doping controls and supporting national testing programs; encouraging the establishment of "best practice" in the labelling, marketing, and distribution of products that might contain prohibited substances; withholding financial support from those who engage in or support doping; taking measures against manufacturing and trafficking; encouraging the establishment of codes of conduct for professions relating to sport and anti-doping; and funding education and research. Criticism Statistical validity of tests Professor Donald A. Berry has argued that the closed systems used by anti-doping agencies do not allow statistical validation of the tests. This argument was seconded by an accompanying editorial in the journal Nature (7 August 2008).