ET9_WebGL_Base/Book/Example/Example3_5/Example3_5.csproj

<Project Sdk="Microsoft.NET.Sdk">

    <PropertyGroup>
        <OutputType>Exe</OutputType>
        <TargetFramework>netcoreapp3.0</TargetFramework>
    </PropertyGroup>

    <ItemGroup>
      <ProjectReference Include="..\..\..\Server\Model\Server.Model.csproj" />
      <ProjectReference Include="..\..\..\Server\ThirdParty\MongoDBDriver\MongoDB.Bson\MongoDB.Bson.csproj" />
    </ItemGroup>

</Project>