.NET Core 1.1: Nuget unable to restore local package

Question

I have a .NET core 1.1.2 app that package references to two other .NET core 1.1.2 apps. Here's my csproj:

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

<ItemGroup>
    <PackageReference Include="../DataAccess/DapperORM/DapperORM.csproj" />
    <PackageReference Include="../Models/Models.csproj" />
</ItemGroup>

<PropertyGroup>
    <TargetFramework>netcoreapp1.1</TargetFramework>
</PropertyGroup>

<ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore" Version="1.1.2" />
    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="1.1.2" />
    <PackageReference Include="System.Data.SqlClient" Version="4.4.2" />
</ItemGroup>

</Project>

It's able to restore the three packages near the bottom just fine, but cannot restore the two local ones near the top. I don't know why.

The exact error I get is:

Error   NU1101  Unable to find package 
../DataAccess/DapperORM/DapperORM.csproj. No packages exist with this id in 
source(s): C:\Program Files\dotnet\sdk\NuGetFallbackFolder, Microsoft Visual 
Studio Offline Packages, nuget.org

The error appears for the Models.csproj as well. I'm using Visual Studio Community 2017 in Windows 10. In the VS Installer, under ASP.NET and web development, I have both .NET Core 2.0 development tools as well as .NET Core 1.0 - 1.1 development tools for Web installed. The same for the .NET Core cross-platform development category.

Any thoughts? Thanks!