Can't find Microsoft.SqlServer.ConnectionInfo.dll assembly file?

I'm trying to dynamically get a databases Table structure using only C# code as follows:

using Microsoft.SqlServer.Management.Common;
using Microsoft.SqlServer.Management.Smo;

public class LoadStuff
{
    ...
    public void LoadDatabase(string vDatabaseName)
    {
        using (var vSqlConnection = new SqlConnection(DatabaseConnectionString))
        {
            var vConnection = new ServerConnection(vSqlConnection);
            var vServer = new Server(vConnection);
            var vDatabase = vServer.Databases[vDatabaseName];
            var vTables = vDatabase.Tables;
        }
    }
}

However, I cannot find the .dll file to add a reference too. I'm using Visual Studio 2010 Professional. Any suggestions?

It is located in c:\program files\microsoft sql server\xxx\sdk\assemblies on my machine. Where xxx is the SQL Server version number (90 or 100). Not sure how it got there.

UPDATE: it has been replaced by SMO (SQL Server Management Objects). The Nuget package is here. Follow the first link for documentation.