django - 「manage.py sqlall」がアプリを認識しないのはなぜですか?

Question

syncdb にインストールされ、シェル django.conf.settings.INSTALLED_APPS を介してアプリが表示されるが、sqlall コマンドでは表示されないのは、どのような状況ですか?

以下に、紛らわしい状況を示す端末出力を貼り付けました。

$ manage.py syncdb
Syncing...
Creating tables ...
Installing custom SQL ...
Installing indexes ...
No fixtures found.

Synced:
 > django.contrib.auth
 > django.contrib.contenttypes
 > django.contrib.sessions
 > django.contrib.sites
 > django.contrib.messages
 > django.contrib.staticfiles
 > django.contrib.admin
 > django.contrib.admindocs
 > django.contrib.gis
 > south
 > django_extensions
 > debug_toolbar
 > django_countries
 > myapp.apps.core

Not synced (use migrations):
 - tastypie
(use ./manage.py migrate to migrate these)
$ manage.py shell

In [1]: from django.conf import settings

In [2]: settings.INSTALLED_APPS
Out[2]:
['django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.sites',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'django.contrib.admin',
 'django.contrib.admindocs',
 'django.contrib.gis',
 'django.contrib.humanize',
 'south',
 'django_extensions',
 'debug_toolbar',
 'tastypie',
 'django_countries',
 'django_nose',
 'myapp.apps.core',
 'myapp.apps.mobile',
 'myapp.apps.api']

In [3]:
Do you really want to exit ([y]/n)? y
$ manage.py sqlall myapp.apps.core
Error: App with label myapp.apps.core could not be found. Are you sure your INSTALLED_APPS setting is correct?