O    ↑
O-WORM	OAI (10)
OAI-PMH (14)	OAIS
OAK	OAK2
OASE	OASIS (4)
ÖB	Oberon
OBIRS	OBIS
Object Analyzer	ÖBV (2)
OBVSG	OCLC (71)
OCLC CJK (2)	OCLC CJK PLus (2)
OCLC InterCat -> InterCat	OCLC Online Union Catalog
OCLC SiteSearch (5)	OCLC Suite
OCLC WorldCat -> WorldCat	OCR (12)
OCSI	ODA (7)
ODA/ODIF	ODIN (2)
ODMG	OECD-Thesaurus
Office Manager Pro	OhioLINK (11)
OIL (4)	OilEd
OILEd 2.2a	Oingo (6)
OIRS	OKAPI (44)
Ökobase	Ökobase Multimedia
Ökobase Umweltatlas	OKRA's Net Citizen Directory
OLAC	OliSuite/WeCat
OLIVE	OLIVER (2)
OLIX	OLUC (12)
Omeka	OML
OMNI	OmniFind
Omnigator	Omnis Quartz
Omnis Studio	Omnis-Myriad
OMNIS/Myriad (4)	OmniSearch
OmnisMyriad	OMRAS
On-line Books	ÖNB (4)
ONCO	ONDEX
ONE (8)	OneLook Dictionaries
OneNote	ONIX (3)
Online-expert (2)	ÖNORM A 2663
OntoBuilder	OntoEdit
OntoEdit 2.0	Ontogator
OntoIOp (2)	OntoM4IS
OntoMathPro	OntoNotes
OntoPhoto	Ontopia (3)
Ontopia Omnigator => Omnigator	OntoSeek
OntoShare	OntoStudio
Ontoverse	OntoViz
OntoWeb (2)	OntoWiki
OPAC	OPAL (3)
Opel	Open Access Helper
Open Alex	Open Citation project
Open Directory (4)	Open Directory Project (2)
Open DRANET (2)	Open Research Knowledge Graph
Open Sesame's eGenie	Open WorldCat (2)
OpenAI (2)	OpenAIRE
OpenCat	OpenCitations
OpenCyc	OpenPGP
OpenRefine	OpenSearch/A9
OpenText (28)	OpenURL (3)
OptiDisk	OPTIMA
OptiqueVQS	Optisearch
Optiware (2)	Optosof
OPUS (3)	OPUSSoIr
OQL	ORACLE (3)
Oracle Server	ORBIS
ORCID (13)	ORCID DE
ORCID DE 2 (2)	ORION
OS/2 Merlin	OSCAR
OSI (14)	OSIRIS (8)
osivo	Österreichischer Bibliothekenverbund
ÖSWD (5)	Otto-Bildarchiv
Otto-Katalog	Overture (2)
OverView	OVID (13)
Ovid Local Leader	ÖVK (2)
ÖVK-WB	OWL (45)
OWL 2 (2)	OWL2
OWLPropViz	Oxford English dictionary (2)
Oxford Interactive Encyclopedia	Oxygen XML Editor 2.0
ÖZDB (5)
P    ↑
P-Rank	P.M. Enzyklopädie 2006
PACE	PACLink (2)
PACS (3)	PADOK (5)
PADOK-II	PageKeeper
PageMill	PageRank (28)
PAIS (5)	Pajek
PAL/MONO-TOC	PALS (2)
PAN (2)	PAN-Klassifikation (2)
Pandia	PANDORA (2)
Panizzi-Regeln (10)	Paper Mills
Paperball (3)	Paperboy (2)
PaperChase	Paperpile
PaperPoles	Paprika
Papyrus (6)	Paraben's Text Searcher
PARADOKS	Paradox (3)
ParaSite	Paris Principles (4)
PARIS-Klassifikation	Parson Technology's Directory
PARTHES (4)	PASSAT (6)
PASSPORT	PATDPA
Pathfinder (3)	PATIS
PATOS	PATSOFT
PAUX	PB-Bibliothek
PC Bibliothek	PC-Bibliothek
PC-File Plus	pcAnywhere (2)
PCC	PCI (2)
PDF (4)	PDF/A
PDS (2)	PERCIRS
Periodensystem der Elemente	PeriodO
Perl (5)	Permuterm Subject Index
PerSavant	Perseus (3)
Perseus Project	Persistent Identifier
Personal Librarian (6)	Personal Library Software (2)
Personal Translator (2)	Personal Translator 2000
PerspectiveWall (2)	PET (3)
Peter's XML Editor	PETRUS (5)
Pfaff-Archiv	PfleSaurus (2)
PGP (13)	Phaidra (2)
Phantom	PharmSearch
Pharos	PHILIS (2)
Phoenix 2.1	Phone Find
PhoneDisc	PhoneSearch USA
Photo Mechanic	Photo-CD
Photoshop	PHP (2)
PHP-Nuke	PHPCMS
PHYS (2)	PHYS/PILOT
PhysDoc	Physics and Astronomy Classification Scheme
Physics Subject Headings	PhysNet
PI (9)	Pic'Lite 1.0
PICA (38)	PICA/ILTIS
PiCarta (2)	PicoSearch
PICS (2)	PICTION
Pictura Paedagogica Online	PICTURE CARDBOX
PICTURE POWER	PictureBase 1.5
PictureProwler 1.1	PID
Pierer's Universal-Lexikon	PIKaDO (2)
PilotBoat	PimEyes
PIRCS	Pl@giarism (www.rechten.unimaas.nl/edit/ICT/Plagiarism
Plaff	Plagiarism-Finder (www.m4-software.de)
Planet	Planet Erde (2)
Planet Multicast	PLEXUS (3)
PLOS ONE (2)	PLS
PLURV	Plus
PND (44)	Pocket Feed
PoemFinder	Poet
PoeTryMe	Point (6)
Pointcast	POINTER
Polar Rose	Polianthes (3)
PoolParty	POPLINE
POPSI (14)	Porter-Stemmer
POS-Tagging	PostgreSQL
Power Translator Pro (2)	Powerbuilder
Powerpoint (3)	Powerroute
PowerRouting 2002	PowerSearch (2)
PPIAK	Prairienet
PRECIS (59)	Precision One MediaSource
PrecisionOne	Preisauskunft.de
Preissuchmaschine.de	Preistester.de
Prelinger Library	PREMARC (2)
PREMIS	Premuim News
Presitrend.de	PRESSoo
Prestel	PRESTO
PriceRunner	Primo (18)
PRIMUS	PRIMUS-IDX
PRINDEX	PRISE
PRISM (17)	Pro-Cite (22)
ProBase	Prochiv
ProCite (13)	ProCite 5.0
Procomm + 1.01	Procomm plus
Prodigy (2)	Professional Software
ProfessionalSeries	Profilatlas Deutschland
ProfNet	Profound
Profusion (4)	Project Jefferson
Projekt Gutenberg (6)	Prolog (4)
Prometheus (3)	Promoware
PROMPT (2)	PromptCat (3)
Promt Online Translator	ProPrint
ProQuest (11)	ProQuest Searchware 4.0
Protégé (11)	Protégé 2000 1.6.2
PROTERM (5)	PS
Pschyrembel	PsychINFO
PsychSpider	PsycINFO (4)
PsycLIT (2)	PsyDok
PsyLIT	Psyndex (5)
Ptolemy 1	PUBLICAT
PubMed (15)	PubMed Central
PubPeer	PubPharm
PubSearch	PUMA
PURL (7)	Python (2)
Q    ↑
Q&A	Q-Analysis (2)
QBIC (9)	Qjumper
QPict Media Organizer	QR-Diagramm
Quaero (4)	QUALCAT (2)
Qualinka	QuarkXPress
QUARTET	Quelle-Katalog
Questel	Questel-Orbit (2)
Question-Master	QuestionPoint (3)
QUESTQUORUM	Quickbrowse
QuickFind	QuickSearch
QuickTime (2)	QUIMaS
QuizRDF (3)	Quora
Qurator	QVIZ
R    ↑
R-Index	Rabbit
RABE (3)	RAD (4)
RADA (2)	RADAR
RaDT	RAK (100)
RAK online	RAK-AV (9)
RAK-Körperschaften	RAK-Musik (18)
RAK-NBM (17)	RAK-ÖB (2)
RAK-Online (10)	RAK-WB (21)
RAK2 (6)	RAMEAU (28)
Rand McNally's New Millennium World Atlas -> New Millennium World Atlas	RAPDOC (4)
RARE	RBSE
RDA (182)	RDA Toolkit (6)
RDD	RDF (78)
RDFa	RDFS (3)
RDK (4)	ReachOut
Reader interest classification (11)	Readers' guide to periodical literature
READWARE	REALIST (3)
RealNames	RealSystem
REBUS	RecallPlus
Reclams Lexikon des deutschen Films	RECOIN
Recolecta	Recommender-Systeme (3)
RediReference (2)	Reference Expert (3)
Reference Manager (16)	Reference Manager 9.5
REFSIM	RefWorks (4)
Regelwerk Fernsehen (3)	Regelwerk Hörfunk
Regelwerk Musik	Regensburger Verbundklassifikation -> SURegensburg
RegioMap	REICAT
Reiseplaner Europa	Reiseplanung
Reiseroute	RELATIO/IR (6)
RelExt	Remembrance Agent
RemotelyPossible	Renardus (14)
Répertoire de vedettes-matière (4)	RERO (2)
RESADIR	Research Papers in Economics
ResearchGate (8)	RESEDA (3)
Resource Discovery Network	ResourceLibrarian
RETRANS	RetrievalWare -> Convera RetrievalWare
RetrievalWare -> Excalibur RetrievalWare	Retriever
Retro-VK (2)	RETROCON (2)
Retrospect	Retrospect 2001 (Spiegel Online)
Retrospect 2002	REUSE (3)
Reuters	RFID (3)
RFK	RiC-CM
RICH	RIDDLE
RILM	RIMMF (5)
RIP	RISM (6)
RLG (3)	RLIM
RLIN (9)	RLIN CJK (2)
RMS-3	RNA (6)
RNAB (3)	Roadscout 2000
robotron*BIDOK/M	Rocchio-Algorithmus (3)
Rocchio-Feedback-Algorithmus	Roche-Lexikon
Rocket eBook (4)	RODIN
Roget's Thesaurus (2)	Röhrich (3)
ROMEO	Romso.de
ROMware	ROOT Thesaurus (2)
Rosetta	RosettaNet
ROSS (2)	rottenneighbor.com
Route 66	Route&Plan
Routenplaner Deutschland	RPVZ
RSS (3)	RSWK (184)
RSWK-Musik (7)	RTFact
RTFtoHTML	Rubik Cube (3)
Ruby	RUDI
RusDML	Russian Science Citation Index
RUSSIAPAT	RVK (37)
RVK s. auch SURegensburg	RVM (2)
RWF -> Regelwerk Fernsehen