diff --git a/doab_check/admin.py b/doab_check/admin.py
index e529bb5..6e16513 100644
--- a/doab_check/admin.py
+++ b/doab_check/admin.py
@@ -1,12 +1,49 @@
 from django.contrib import admin
+from django.utils.safestring import mark_safe
 
 # Register your models here.
 
 from . import models 
 
-admin.site.register(models.Item)
-admin.site.register(models.Link)
-admin.site.register(models.Timestamp)
-admin.site.register(models.Record)
-admin.site.register(models.LinkRel)
-admin.site.register(models.Check)
+
+@admin.register(models.Check)
+class CheckAdmin(admin.ModelAdmin):
+    list_display = ('link_url', 'return_code', 'content_type')
+    date_hierarchy = 'created'
+    search_fields = ['return_code']
+    ordering = ('created', 'return_code', 'content_type')
+    readonly_fields = ('link_url', 'return_code', 'content_type', 'link', 'location')
+    def link_url(self, obj):
+        return mark_safe(f'<a href="/admin/doab_check/link/{obj.link.id}/">{obj.link.url}</a>')
+
+@admin.register(models.Item)
+class ItemAdmin(admin.ModelAdmin):
+    list_display = (str, 'title', 'resource_type')
+    date_hierarchy = 'created'
+    search_fields = ['title']
+
+@admin.register(models.Link)
+class LinkAdmin(admin.ModelAdmin):
+    list_display = ('url', 'provider')
+    date_hierarchy = 'created'
+    search_fields = ['url']
+    exclude = ['url']
+    readonly_fields = ('link_display', 'provider')
+    def link_display(self, obj):
+        return mark_safe(f'<a href="{obj.url}">{obj.url}</a>')
+
+@admin.register(models.LinkRel)
+class LinkAdmin(admin.ModelAdmin):
+    list_display = ('role', 'doab', 'url',)
+    readonly_fields = ('doab', 'url')
+    search_fields = ['link__url']
+    def doab(self, obj):
+        return mark_safe(f'<a href="/admin/doab_check/item/{obj.item.id}/">{obj.item}</a>')
+    def url(self, obj):
+        return mark_safe(f'<a href="/admin/doab_check/link/{obj.link.id}/">{obj.link.url}</a>')
+
+@admin.register(models.Record)
+class RecordAdmin(admin.ModelAdmin):
+    readonly_fields = ['item']
+
+
diff --git a/doab_check/check.py b/doab_check/check.py
new file mode 100755
index 0000000..b9f17e7
--- /dev/null
+++ b/doab_check/check.py
@@ -0,0 +1,119 @@
+#!/usr/bin/env python
+# encoding: utf-8
+
+import logging
+import re
+import time
+from urllib.parse import urlparse
+
+import requests
+
+from django.conf import settings
+
+from .models import Check, Link
+
+HEADERS = {"User-Agent": settings.USER_AGENT}
+
+DELAYS = {
+    'oapen.org': 0.05,
+    '*': 0.5,
+}
+
+logger = logging.getLogger(__name__)
+
+class ContentTyper(object):
+    """ won't make more checks faster than the DELAY set for the host """
+    def __init__(self):
+        self.last_call = dict()
+
+    def content_type(self, url):
+        try:
+            r = requests.head(url, allow_redirects=True, headers=HEADERS)
+            if r.status_code == 405:
+                r =  requests.get(url, headers=HEADERS)
+            return r
+        except:
+            # unexplained error
+            return None
+
+    def calc_type(self, url):
+        logger.info(url)
+        # is there a delay associated with the url
+        netloc = urlparse(url).netloc
+        delay = DELAYS.get(netloc, DELAYS.get('*'))
+
+        # wait if necessary
+        last_call = self.last_call.get(netloc)
+        if last_call is not None:
+            now = time.time()
+            min_time_next_call = last_call + delay
+            if min_time_next_call > now:
+                time.sleep(min_time_next_call-now)
+
+        self.last_call[netloc] = time.time()
+
+        # compute the content-type
+        
+        return self.content_type(url)
+
+contenttyper = ContentTyper()
+
+RE_EBOOK_TYPES = re.compile(r'(epub|pdf|mobi)', flags=re.I)
+
+def response_parts(response):
+    ''' return code, content type, content disposition handling any missing data'''
+    if response == None:
+        return 0, '', ''
+    try:
+        if response.status_code == 404:
+            return 404, '', ''
+        cdisp = response.headers.get('content-disposition', '')
+        return response.status_code, response.headers.get('content-type', ''), cdisp
+    except:
+        return response.status_code, '', ''
+    
+
+
+def type_for_url(url, response=None):
+    ''' check a url to see what's there. the content-disposition header is often needed to 
+        dermine the type of file i.e. pdf, epub, etc. at the end of the link '''
+    if not url and not response:
+        return ''
+
+    if response:
+        code, ct, disposition = response_parts(response)
+        url = response.url
+    else:
+        code, ct, disposition = response_parts(contenttyper.calc_type(url))
+    url_disp = url + disposition
+    if code == 404:
+        return 404, ''
+    binary_type = re.search("octet-stream", ct) or re.search("application/binary", ct)
+    ebook_type_match = RE_EBOOK_TYPES.search(url_disp)
+    if re.search("pdf", ct):
+        return code, "pdf"
+    elif binary_type and ebook_type_match:
+        return code, ebook_type_match.group(1).lower()
+    elif re.search("text/plain", ct):
+        return code, "text"
+    elif re.search("text/html", ct):
+        return code, "html"
+    elif re.search("epub", ct):
+        return code, "epub"
+    elif re.search("mobi", ct):
+        return code, "mobi"
+    # no content-type header?
+    elif ebook_type_match:
+        return code, ebook_type_match.group(1).lower()
+
+    return code, f'other; {ct}'
+
+def check_link(link):
+    ''' given a Link object, check it's URL, put the result in a Check object '''
+    check = Check(link=link)
+    code, ct =  type_for_url(link.url)
+    check.return_code = code
+    check.content_type = ct
+    check.save()
+    
+    
diff --git a/doab_check/management/commands/check_some_links.py b/doab_check/management/commands/check_some_links.py
new file mode 100644
index 0000000..14fd219
--- /dev/null
+++ b/doab_check/management/commands/check_some_links.py
@@ -0,0 +1,21 @@
+import datetime
+from django.core.management.base import BaseCommand
+
+from doab_check.check import check_link
+from doab_check.models import Link
+
+class Command(BaseCommand):
+    help = "check links in rando. order"
+
+    def add_arguments(self, parser):
+        parser.add_argument('--max', nargs='?', type=int, default=1000, help="max checks")
+
+    def handle(self, **options):
+        max = options['max']
+        n_checked = 0
+        for link in Link.objects.all().order_by('?'):
+            check_link(link)
+            n_checked += 1
+            if n_checked >= max:
+                break
+        self.stdout.write(f'checked {n_checked} links')
diff --git a/doab_check/models.py b/doab_check/models.py
index bc77f50..f204112 100644
--- a/doab_check/models.py
+++ b/doab_check/models.py
@@ -16,6 +16,9 @@ class Item(models.Model):
     
     # titles can change
     title = models.CharField(max_length=1000)
+    
+    def __str__(self):
+        return self.doab.split('/')[1] if '/' in self.doab else self.doab
 
 class Link(models.Model):
     ''' these are the links we're going to check '''
@@ -25,7 +28,6 @@ class Link(models.Model):
     # the items reporting this link
     items = models.ManyToManyField("Item", related_name="links", db_index=True, through="LinkRel")
 
-
     # so we can set it to dead instead of deleting
     live = models.BooleanField(default=True)
     
@@ -40,17 +42,24 @@ class Link(models.Model):
             self.provider = netloc
         super().save(*args, **kwargs)
 
+
 class Timestamp(models.Model):
     ''' timestamp of the record returned by doab. records can have multiple timestamps '''
     created = models.DateTimeField(auto_now_add=True)
     datetime =  models.DateTimeField()
     record = models.ForeignKey("Record", related_name="timestamps", null=False,
                                on_delete=models.CASCADE)
+    def __str__(self):
+        return f'Record for {self.record.item} on {self.datetime}'
+
 
 class Record(models.Model):
     ''' a harvested record '''
     created = models.DateTimeField(auto_now_add=True)
     item = models.ForeignKey("Item", related_name="records", on_delete=models.CASCADE)
+    def __str__(self):
+        return f'Record for {self.item} harvested on {self.created}'
+    
 
 class LinkRel(models.Model):
     ''' association between an item and a link '''