-- Database schema
| Country : CountryCode [ TEXT ] primary_key , ShortName [ TEXT ] , TableName [ TEXT ] , LongName [ TEXT ] , Alpha2Code [ TEXT ] , CurrencyUnit [ TEXT ] , SpecialNotes [ TEXT ] , Region [ TEXT ] , IncomeGroup [ TEXT ] , Wb2Code [ TEXT ] , NationalAccountsBaseYear [ TEXT ] , NationalAccountsReferenceYear [ TEXT ] , SnaPriceValuation [ TEXT ] , LendingCategory [ TEXT ] , OtherGroups [ TEXT ] , SystemOfNationalAccounts [ TEXT ] , AlternativeConversionFactor [ TEXT ] , PppSurveyYear [ TEXT ] , BalanceOfPaymentsManualInUse [ TEXT ] , ExternalDebtReportingStatus [ TEXT ] , SystemOfTrade [ TEXT ] , GovernmentAccountingConcept [ TEXT ] , ImfDataDisseminationStandard [ TEXT ] , LatestPopulationCensus [ TEXT ] , LatestHouseholdSurvey [ TEXT ] , SourceOfMostRecentIncomeAndExpenditureData [ TEXT ] , VitalRegistrationComplete [ TEXT ] , LatestAgriculturalCensus [ TEXT ] , LatestIndustrialData [ INTEGER ] , LatestTradeData [ INTEGER ] , LatestWaterWithdrawalData [ INTEGER ] | Series : SeriesCode [ TEXT ] primary_key , Topic [ TEXT ] , IndicatorName [ TEXT ] , ShortDefinition [ TEXT ] , LongDefinition [ TEXT ] , UnitOfMeasure [ TEXT ] , Periodicity [ TEXT ] , BasePeriod [ TEXT ] , OtherNotes [ INTEGER ] , AggregationMethod [ TEXT ] , LimitationsAndExceptions [ TEXT ] , NotesFromOriginalSource [ TEXT ] , GeneralComments [ TEXT ] , Source [ TEXT ] , StatisticalConceptAndMethodology [ TEXT ] , DevelopmentRelevance [ TEXT ] , RelatedSourceLinks [ TEXT ] , OtherWebLinks [ INTEGER ] , RelatedIndicators [ INTEGER ] , LicenseType [ TEXT ] | CountryNotes : Countrycode [ TEXT ] CountryNotes.Countrycode = Country.CountryCode , Seriescode [ TEXT ] CountryNotes.Seriescode = Series.SeriesCode , Description [ TEXT ] | Footnotes : Countrycode [ TEXT ] Footnotes.Countrycode = Country.CountryCode , Seriescode [ TEXT ] Footnotes.Seriescode = Series.SeriesCode , Year [ TEXT ] , Description [ TEXT ] | Indicators : CountryName [ TEXT ] , CountryCode [ TEXT ] Indicators.CountryCode = Country.CountryCode , IndicatorName [ TEXT ] , IndicatorCode [ TEXT ] , Year [ INTEGER ] , Value [ INTEGER ] | SeriesNotes : Seriescode [ TEXT ] SeriesNotes.Seriescode = Series.SeriesCode , Year [ TEXT ] , Description [ TEXT ] |
-- -- What are the subjects of series that have a restricted type of license?

SELECT DISTINCT Topic FROM Series WHERE LicenseType = 'Restricted';