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      <link:calculationArc
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                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ext_ErgFondoBusinessDismessi"
                            weight="1.0"
                            order="29.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DeferredTaxLiabilities" xlink:label="ifrs-full_DeferredTaxLiabilities" xlink:type="locator"/>
      <link:calculationArc
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                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ifrs-full_DeferredTaxLiabilities"
                            order="30.0"
                            weight="1.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherNoncurrentFinancialLiabilities" xlink:label="ifrs-full_OtherNoncurrentFinancialLiabilities" xlink:type="locator"/>
      <link:calculationArc
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                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ifrs-full_OtherNoncurrentFinancialLiabilities"
                            order="50.0"
                            weight="1.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherNoncurrentNonfinancialLiabilities" xlink:label="ifrs-full_OtherNoncurrentNonfinancialLiabilities" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ifrs-full_OtherNoncurrentNonfinancialLiabilities"
                            order="60.0"
                            weight="1.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentProvisionsForEmployeeBenefits" xlink:label="ifrs-full_NoncurrentProvisionsForEmployeeBenefits" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ifrs-full_NoncurrentProvisionsForEmployeeBenefits"
                            weight="1.0"
                            order="61.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_LongtermProvisionForDecommissioningRestorationAndRehabilitationCosts" xlink:label="ifrs-full_LongtermProvisionForDecommissioningRestorationAndRehabilitationCosts" xlink:type="locator"/>
      <link:calculationArc
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                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ifrs-full_LongtermProvisionForDecommissioningRestorationAndRehabilitationCosts"
                            weight="1.0"
                            order="62.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherLongtermProvisions" xlink:label="ifrs-full_OtherLongtermProvisions" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ifrs-full_OtherLongtermProvisions"
                            weight="1.0"
                            order="63.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentDerivativeFinancialLiabilities" xlink:label="ifrs-full_NoncurrentDerivativeFinancialLiabilities" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ifrs-full_NoncurrentDerivativeFinancialLiabilities"
                            weight="1.0"
                            order="64.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentLeaseLiabilities" xlink:label="ifrs-full_NoncurrentLeaseLiabilities" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ifrs-full_NoncurrentLeaseLiabilities"
                            weight="1.0"
                            order="65.0"
                          xlink:type="arc"/>
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   <link:calculationLink xlink:role="https://www.erg.eu/xbrl/role/all/ias_1_role-210000" xlink:type="extended">
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_Assets" xlink:label="ifrs-full_Assets" xlink:type="locator"/>
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentAssets" xlink:label="ifrs-full_NoncurrentAssets" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item"
                          xlink:from="ifrs-full_Assets"
                          xlink:to="ifrs-full_NoncurrentAssets"
                            order="10.0"
                            weight="1.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CurrentAssets" xlink:label="ifrs-full_CurrentAssets" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item"
                          xlink:from="ifrs-full_Assets"
                          xlink:to="ifrs-full_CurrentAssets"
                            order="20.0"
                            weight="1.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleOrAsHeldForDistributionToOwners" xlink:label="ifrs-full_NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleOrAsHeldForDistributionToOwners" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item"
                          xlink:from="ifrs-full_Assets"
                          xlink:to="ifrs-full_NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleOrAsHeldForDistributionToOwners"
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                            order="21.0"
                          xlink:type="arc"/>
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   <link:calculationLink xlink:role="https://www.erg.eu/xbrl/role/all/ias_1_role-210000" xlink:type="extended">
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentAssets" xlink:label="ifrs-full_NoncurrentAssets" xlink:type="locator"/>
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_PropertyPlantAndEquipment" xlink:label="ifrs-full_PropertyPlantAndEquipment" xlink:type="locator"/>
      <link:calculationArc
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                          xlink:from="ifrs-full_NoncurrentAssets"
                          xlink:to="ifrs-full_PropertyPlantAndEquipment"
                            order="10.0"
                            weight="1.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_Goodwill" xlink:label="ifrs-full_Goodwill" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentAssets"
                          xlink:to="ifrs-full_Goodwill"
                            order="30.0"
                            weight="1.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="8156004604684CA44A90-2021-12-31.xsd#ext_ErgAutorizzazioniEConcessioni" xlink:label="ext_ErgAutorizzazioniEConcessioni" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentAssets"
                          xlink:to="ext_ErgAutorizzazioniEConcessioni"
                            weight="1.0"
                            order="99.98"
                          xlink:type="arc"/>
      <link:loc xlink:href="8156004604684CA44A90-2021-12-31.xsd#ext_ErgPartecipazioni" xlink:label="ext_ErgPartecipazioni" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentAssets"
                          xlink:to="ext_ErgPartecipazioni"
                            weight="1.0"
                            order="99.99"
                          xlink:type="arc"/>
      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DeferredTaxAssets" xlink:label="ifrs-full_DeferredTaxAssets" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentAssets"
                          xlink:to="ifrs-full_DeferredTaxAssets"
                            order="100.0"
                            weight="1.0"
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      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherNoncurrentFinancialAssets" xlink:label="ifrs-full_OtherNoncurrentFinancialAssets" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentAssets"
                          xlink:to="ifrs-full_OtherNoncurrentFinancialAssets"
                            order="120.0"
                            weight="1.0"
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      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherNoncurrentNonfinancialAssets" xlink:label="ifrs-full_OtherNoncurrentNonfinancialAssets" xlink:type="locator"/>
      <link:calculationArc
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                          xlink:from="ifrs-full_NoncurrentAssets"
                          xlink:to="ifrs-full_OtherNoncurrentNonfinancialAssets"
                            order="130.0"
                            weight="1.0"
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      <link:loc xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_RightofuseAssets" xlink:label="ifrs-full_RightofuseAssets" xlink:type="locator"/>
      <link:calculationArc
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                          xlink:from="ifrs-full_NoncurrentAssets"
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                            weight="1.0"
                            order="131.0"
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                          xlink:from="ifrs-full_NoncurrentAssets"
                          xlink:to="ifrs-full_OtherIntangibleAssets"
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                            order="132.0"
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      <link:calculationArc
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                          xlink:from="ifrs-full_NoncurrentAssets"
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                          xlink:to="ifrs-full_OtherCurrentFinancialAssets"
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                          xlink:to="ifrs-full_CashAndCashEquivalents"
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                          xlink:from="ifrs-full_EquityAndLiabilities"
                          xlink:to="ifrs-full_Equity"
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   <link:calculationLink xlink:role="https://www.erg.eu/xbrl/role/all/ias_1_role-210000" xlink:type="extended">
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                          xlink:from="ifrs-full_Equity"
                          xlink:to="ifrs-full_EquityAttributableToOwnersOfParent"
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                          xlink:to="ifrs-full_NoncontrollingInterests"
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