author: Javier Tamames  Ugo Bastolla  Alberto Pascual-García 

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copyrighted in Singapore.

copyrighted in Argentina.

copyrighted in Trinidad and Tobago.

copyrighted in Saint Vincent and the Grenadines.

copyrighted in United States.

copyrighted in Uruguay.

copyrighted in Bulgaria.

copyrighted in Slovakia.

copyrighted in Nauru.

copyrighted in Austria.

copyrighted in Cyprus.

copyrighted in Bosnia and Herzegovina.

copyrighted in Latvia.

copyrighted in Belgium.

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copyrighted in Brazil.

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copyrighted in Guyana.

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copyrighted in Luxembourg.

copyrighted in India.

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copyrighted in Federated States of Micronesia.

copyrighted in Spain.

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copyrighted in Switzerland.

copyrighted in Japan.

copyrighted in Czech Republic.

copyrighted in Saint Kitts and Nevis.

copyrighted in Finland.

copyrighted in Timor-Leste.

copyrighted in Cuba.

copyrighted in Antigua and Barbuda.

copyrighted in Mongolia.

copyrighted in Honduras.

copyrighted in Slovenia.

copyrighted in Russia.

copyrighted in Norway.

copyrighted in France.

copyrighted in Sweden.

copyrighted in Ecuador.

copyrighted in Solomon Islands.

copyrighted in Poland.

copyrighted in Italy.

copyrighted in Belarus.

copyrighted in Indonesia.

copyrighted in Egypt.

copyrighted in Paraguay.

copyrighted in Jamaica.

copyrighted in Bolivia.

copyrighted in Samoa.

copyrighted in El Salvador.

copyrighted in Kazakhstan.

copyrighted in North Macedonia.

copyrighted in Hungary.

copyrighted in Vatican City.

copyrighted in Australia.

copyrighted in South Africa.

copyrighted in Estonia.

copyrighted in Montenegro.

copyrighted in Saint Lucia.

copyrighted in Armenia.

copyrighted in Grenada.

copyrighted in Iceland.

copyrighted in Canada.

copyrighted in North Korea.

copyrighted in Ghana.

copyrighted in Chile.

copyrighted in Bahrain.

copyrighted in Vanuatu.

copyrighted in Ireland.

copyrighted in Dominica.

copyrighted in countries with longer than 60 years pma.

copyrighted in countries with longer than 80 years pma.

copyrighted in countries with longer than 85 years pma.

copyrighted in countries with 71.5 years copyright term after publication.

copyrighted in countries with 25 years pma.

copyrighted in countries with 45 years pma or shorter.

copyrighted in countries with 70 years copyright term after publication.

copyrighted in countries with 60 years pma or shorter.

copyrighted in countries with 74 years copyright term after publication.

copyrighted in countries with 90 years pma or shorter.

copyrighted in countries with 25 years copyright term after publication.

copyrighted in countries with 95 years copyright term after publication.

copyrighted in countries with 75 years pma.

copyrighted in countries with 75 years pma or shorter.

copyrighted in countries with longer than 75 years pma.

copyrighted in countries where faithful reproduction of a 2D work of art do not have additional copyrights.

copyrighted in countries with 95 years pma or shorter.

copyrighted in countries with 20 years copyright term after publication.

copyrighted in countries with 60 years copyright term after publication.

copyrighted in countries with longer than 25 years pma.

copyrighted in countries with 30 years pma or shorter.

copyrighted in countries with 30 years pma.

copyrighted in countries with longer than 30 years pma.

copyrighted in countries with 85 years pma.

copyrighted in countries with longer than 74 years pma.

copyrighted in countries with 78 years pma or shorter.

copyrighted in countries with 50 years pma.

copyrighted in countries without PD-art.

copyrighted in countries with 90 years pma.

copyrighted in countries with longer than 90 years pma.

copyrighted in countries with longer than 100 years pma.

copyrighted in countries with 15 years pma.

copyrighted in countries with 45 years pma.

copyrighted in countries with longer than 50 years pma.

copyrighted in countries with 85 years pma or shorter.

copyrighted in countries with 15 years pma or shorter.

copyrighted in countries with longer than 15 years pma.

copyrighted in countries with longer than 45 years pma.

copyrighted in countries with longer than 95 years pma.

copyrighted in countries with 74 years pma or shorter.

copyrighted in countries with 80 years pma.

copyrighted in countries with 60 years pma.

copyrighted in countries with 74 years pma.

copyrighted in countries with 100 years pma.

copyrighted in countries with 50 years copyright term after publication.

copyrighted in countries with 78 years pma.

copyrighted in countries with 95 years pma.

copyrighted in Tarshish.

copyrighted in Chinland.

copyrighted in Philippines.

copyrighted in Kingdom of the Netherlands.

copyrighted in The Gambia.

copyrighted in countries which use the rule of the shorter term.

copyrighted in Brunei.

copyrighted in Afghanistan.

copyrighted in Namibia.

copyrighted in Persia.

copyrighted in Guinea.

copyrighted in Oman.

copyrighted in Uganda.

copyrighted in Free Republic of the Congo.

copyrighted in Qatar.

copyrighted in countries with 50 years pma or shorter.

copyrighted in Nicaragua.

copyrighted in Cook Islands.

copyrighted in Niue.

copyrighted in countries with 100 years pma or shorter.

copyrighted in Turkmenistan.

copyrighted in Burkina Faso.

copyrighted in Liberia.

copyrighted in Somalia.

copyrighted in countries with 25 years pma or shorter.

copyrighted in Cameroon.

copyrighted in Bhutan.

copyrighted in Niger.

copyrighted in Saudi Arabia.

copyrighted in Mozambique.

copyrighted in Zambia.

copyrighted in Eritrea.

copyrighted in Republic of the Congo.

copyrighted in Morocco.

copyrighted in Syria.

copyrighted in Vietnam.

copyrighted in Ivory Coast.

copyrighted in Nigeria.

copyrighted in Nepal.

copyrighted in Central African Republic.

copyrighted in Kosovo.

copyrighted in Bharatpur State.

copyrighted in Sri Lanka.

copyrighted in Mauritius.

copyrighted in Costa Rica.

copyrighted in Maldives.

copyrighted in Yemen.

copyrighted in São Tomé and Príncipe.

copyrighted in Ashkenaz.

copyrighted in countries with 80 years pma or shorter.

copyrighted in Myanmar.

copyrighted in Gabon.

copyrighted in countries with 70 years pma.

copyrighted in countries with 70 years pma or shorter.

copyrighted in Havilah.

copyrighted in Burundi.

copyrighted in Tunisia.

copyrighted in countries with longer than 70 years pma.

copyrighted in Djibouti.

copyrighted in Benin.

copyrighted in Aruba.

copyrighted in Zimbabwe.

copyrighted in Iraq.

copyrighted in Kyrgyzstan.

copyrighted in Republic of Haiti.

copyrighted in Sint Maarten.

copyrighted in Libya.

copyrighted in Malaysia.

copyrighted in Botswana.

copyrighted in Bangladesh.

copyrighted in South Sudan.

copyrighted in Lebanon.

copyrighted in State of Palestine.

copyrighted in Kingdom of Denmark.

copyrighted in Mauritania.

copyrighted in Iran.

copyrighted in Republic of Cuba.

copyrighted in Tanzania.

copyrighted in South Korea.

copyrighted in Democratic Republic of the Congo.

copyrighted in Rwanda.

copyrighted in Pakistan.

copyrighted in Lesotho.

copyrighted in Togo.

copyrighted in Seychelles.

copyrighted in Comoros.

copyrighted in Israel.

copyrighted in Laos.

copyrighted in Tajikistan.

copyrighted in Thailand.

copyrighted in United Arab Emirates.

copyrighted in Mali.

copyrighted in Angola.

copyrighted in Jordan.

copyrighted in Sierra Leone.

copyrighted in Sudan.

copyrighted in Taiwan.

copyrighted in Cape Verde.

copyrighted in Malawi.

copyrighted in Senegal.