how to iterate on dictionary which has a list of values?

Hello;

I have a sample dictionary as follows:

Dictionary<strign, List<string>> recon= new Dictionary<strign, List<string>>();

List<string> referenceId= new List<string>();
referenceId.Add("0001"); 
referenceId.Add("0002"); 
referenceId.Add("0003"); 
referenceId.Add("0004");

List<string> productCode= new List<string>();
productCode.Add("abc"); 
productCode.Add("def"); 
productCode.Add("ght"); 
productCode.Add("yuk");

recon["referenceId"] = referenceId;
recon["productCode"] = productCode;

I am trying to iterate over only referenceId values and get the values. How can I achieve it? By the way is there any shortcut version rather than using 2 for each loops?

var reconResult = await (context.GameBanks.Where(g => g.used == 0)
                .Where(l => l.referenceId != null)
                ).ToListAsync();

if (reconResult.Count() != 0)
{
        foreach (var item in reconResult)
        {
              foreach (KeyValuePair<string, List<string>> entry in recon.Where(r => r.Key == "referenceId"))
                    {
                        if (item.referenceId == entry.Value[0])
                        {
                            //item.used = 1;
                        }
                    }
         }
}

Best Regards.