/FONT#0=BASL30/FONT#1=BASI30/FONT#2=BASB30/FONT#3=FIX30
␈↓␈↓↓␈↓α␈↓β␈↓ αQ␈↓αARTIFICIAL INTELLIGENCE AND THE STANFORD AI LABORATORY␈↓
␈↓ ↓H

␈↓ ↓H

␈↓ ↓H
␈↓ α_This␈αis␈αa␈αgeneral␈αarticle␈αfor␈αanswering␈αinquiries␈αabout␈αartificial␈αintelligence␈αand␈αthe␈αStanford
␈↓ ↓H
␈↓ ↓HArtificial␈α
Intelligence␈α
Laboratory.␈α
We␈α
hope␈α
it␈α
answers␈α
your␈α
questions.
␈↓ ↓H

␈↓ ↓H
␈↓ α_␈↓↓Artificial␈α∀intelligence␈↓␈α∀is␈α∀the␈α∀name␈α∀given␈α∀to␈α∀the␈α∀study␈α∀of␈α∀intellectual␈α∪processes␈α∪and␈α∪how
␈↓ ↓H
␈↓ ↓Hcomputers␈αcan␈αbe␈αmade␈αto␈αcarry␈αthem␈αout.␈αMost␈αworkers␈αin␈αthe␈αfield␈αbelieve␈αthat␈αit␈αwill␈αbe␈αpossible
␈↓ ↓H
␈↓ ↓Hto␈αprogram␈αcomputers␈α
to␈α
carry␈α
out␈α
any␈α
intellectual␈α
process␈α
now␈α
done␈α
by␈α
humans.␈α
However,␈α
almost␈α
all
␈↓ ↓H
␈↓ ↓Hagree␈α
that␈α
we␈α
are␈α
not␈α
very␈α
close␈α
to␈α
this␈αgoal␈αand␈αthat␈αsome␈αfundamental␈αdiscoveries␈αmust␈αbe␈αmade
␈↓ ↓H
␈↓ ↓Hfirst.␈α⊂Therefore,␈α⊂work␈α⊂in␈α⊂AI␈α⊂includes␈α⊂trying␈α⊂to␈α∂analyze␈α∂intelligent␈α∂behavior␈α∂into␈α∂more␈α∂basic␈α∂data
␈↓ ↓H
␈↓ ↓Hstructures␈α∩and␈α∩processes,␈α∩experiments␈α∩to␈α⊃determine␈α⊃if␈α⊃processes␈α⊃proposed␈α⊃to␈α⊃solve␈α⊃some␈α⊃class␈α⊃of
␈↓ ↓H
␈↓ ↓Hproblems␈α
really␈α
work,␈α
and␈α
attempts␈α
to␈α
apply␈α
what␈α
we␈α
have␈α
found␈α
so␈α
far␈α
to␈α
practical␈α
problems.
␈↓ ↓H

␈↓ ↓H
␈↓ α_The␈α
idea␈α
of␈α
intelligent␈α
machines␈α
is␈α
very␈α
old␈αin␈αfiction,␈αbut␈αpresent␈αwork␈αdates␈αfrom␈αthe␈αtime
␈↓ ↓H
␈↓ ↓Hstored␈α∩program␈α∩electronic␈α∩computers␈α∩became␈α∩available␈α⊃starting␈α⊃in␈α⊃1949.␈α⊃Any␈α⊃behavior␈α⊃that␈α⊃can
␈↓ ↓H
␈↓ ↓Hcarried␈αout␈αby␈αany␈αmechanical␈αdevice␈αcan␈αbe␈αdone␈αby␈αa␈αcomputer,␈αand␈αgetting␈αa␈αparticular␈αbehavior
␈↓ ↓H
␈↓ ↓His␈α∪just␈α∪a␈α∪matter␈α∪of␈α∪writing␈α∪a␈α∪program␈α∪unless␈α∩the␈α∩behavior␈α∩requires␈α∩special␈α∩input␈α∩and␈α∩output
␈↓ ↓H
␈↓ ↓Hequipment.␈α∃It␈α∃is␈α∃perhaps␈α∀reasonable␈α∀to␈α∀date␈α∀AI␈α∀from␈α∀A.M.␈α∀Turing's␈α∀1950␈α∀paper,␈α∀␈↓↓Computing
␈↓ ↓H
␈↓ ↓HMachinery␈α∂and␈α∂Intelligence␈↓.␈α∂Newell,␈α∂Shaw␈α∂and␈α∂Simon␈α∞started␈α∞their␈α∞group␈α∞in␈α∞1954␈α∞and␈α∞the␈α∞M.I.T.
␈↓ ↓H
␈↓ ↓HArtificial␈α
Intelligence␈α
Laboratory␈α
was␈α
started␈α
by␈α
McCarthy␈α
and␈α
Minsky␈α
in␈α
1958.
␈↓ ↓H

␈↓ ↓H
␈↓ α_Early␈αwork␈αin␈αAI␈αincluded␈αprograms␈αto␈αplay␈αgames␈αlike␈αchess␈αand␈αcheckers␈αand␈αkalah␈αand␈αgo.
␈↓ ↓H
␈↓ ↓HThe␈αsuccess␈αof␈αthese␈αprograms␈αwas␈αrelated␈αto␈αthe␈αextent␈αthat␈αhuman␈αplay␈αof␈αthese␈αgames␈αmakes␈αuse
␈↓ ↓H
␈↓ ↓Hof␈α∪mechanisms␈α∪we␈α∩didn't␈α∩understand␈α∩well␈α∩enough␈α∩to␈α∩program.␈α∩If␈α∩the␈α∩game␈α∩requires␈α∩only␈α∩well
␈↓ ↓H
␈↓ ↓Hunderstood␈αmechanisms,␈αcomputers␈αplay␈αbetter␈αthan␈αhumans.␈αKalah␈αis␈αsuch␈αa␈αgame.␈αThe␈αbest␈αrating
␈↓ ↓H
␈↓ ↓Hobtained␈α∞in␈α∞tournament␈α∞play␈α∞by␈α∞a␈α∞chess␈α∞program␈α∞so␈α∞far␈α∞is␈α∞around␈α
1700␈α
which␈α
is␈α
a␈α
good␈α
amateur
␈↓ ↓H
␈↓ ↓Hlevel.␈α
The␈α
chess␈α
programmers␈α
hope␈α
to␈α
do␈α
better.
␈↓ ↓H

␈↓ ↓H
␈↓ α_Another␈α∩early␈α∩problem␈α∩domain␈α⊃was␈α⊃theorem␈α⊃proving␈α⊃in␈α⊃logic.␈α⊃This␈α⊃is␈α⊃important␈α⊃for␈α⊃two
␈↓ ↓H
␈↓ ↓Hreasons.␈αFirst,␈αit␈αprovides␈αanother␈αarea␈αin␈αwhich␈α
our␈α
accomplishments␈α
in␈α
artificial␈α
intelligence␈α
can␈α
be
␈↓ ↓H
␈↓ ↓Hcompared␈α↔with␈α↔human␈α↔intelligence.␈α↔Again␈α↔the␈α↔results␈α↔obtained␈α↔depend␈α⊗on␈α⊗what␈α⊗intellectual
␈↓ ↓H
␈↓ ↓Hmechanisms␈αthe␈αtheorem␈αproving␈αrequires,␈αbut␈αin␈αgeneral␈αthe␈αresults␈αhave␈αnot␈αbeen␈αas␈αgood␈αas␈αwith
␈↓ ↓H
␈↓ ↓Hgame␈α∞playing.␈α∞This␈α∞is␈α∞partly␈α∞because␈α∞the␈α∞mathematical␈α
logical␈α
systems␈α
available␈α
were␈α
designed␈α
for
␈↓ ↓H
␈↓ ↓Hproving␈αmetatheorems␈αabout␈αrather␈αthan␈αfor␈αproving␈αtheorems␈αin.␈αThe␈αsecond␈αreason␈αwhy␈αtheorem
␈↓ ↓H
␈↓ ↓Hproving␈α⊃is␈α⊃important␈α⊂is␈α⊂that␈α⊂logical␈α⊂languages␈α⊂can␈α⊂be␈α⊂used␈α⊂to␈α⊂express␈α⊂what␈α⊂we␈α⊂wish␈α⊂to␈α⊂tell␈α⊂the
␈↓ ↓H
␈↓ ↓Hcomputer␈αabout␈αthe␈αworld,␈αand␈αwe␈αcan␈αtry␈αto␈α
make␈α
it␈α
reason␈α
from␈α
this␈α
what␈α
it␈α
should␈α
do␈α
to␈α
solve␈α
the
␈↓ ↓H
␈↓ ↓Hproblems␈αwe␈αgive␈αit.␈αIt␈αturns␈αout␈αto␈αbe␈αquite␈αdifficult␈αto␈αexpress␈αwhat␈αhumans␈α
know␈α
about␈α
the␈α
world
␈↓ ↓H
␈↓ ↓Hin␈αthe␈αpresent␈αlogical␈αlanguages␈αor␈αin␈αany␈αother␈αway.␈αSome␈αof␈αwhat␈αwe␈αknow␈αis␈αreadily␈αexpressed␈αin
␈↓ ↓H
␈↓ ↓Hnatural␈αlanguage,␈αbut␈α
much␈α
basic␈α
information␈α
about␈α
causality␈α
and␈α
what␈α
may␈α
happen␈α
when␈α
an␈α
action
␈↓ ↓H
␈↓ ↓His␈αtaken␈αis␈αnot␈αever␈αexplicitly␈αstated␈αin␈αhuman␈αspeech.␈αThis␈αgives␈αrise␈αto␈αthe␈αrepresentation␈αproblem
␈↓ ↓H
␈↓ ↓Hof␈αdetermining␈αwhat␈αis␈αknown␈αin␈αgeneral␈αabout␈αthe␈αworld␈αand␈αhow␈αto␈αexpress␈αit␈αin␈αa␈αform␈αthat␈αcan
␈↓ ↓H
␈↓ ↓Hbe␈α∞used␈α∞by␈α∞the␈α∞computer␈α∞to␈α∞solve␈α∞problems.␈α∞As␈α∞this␈α
is␈α
written␈α
-␈α
summer␈α
1973␈α
-␈α
the␈α
representation
␈↓ ↓H
␈↓ ↓Hproblem␈α
seems␈α
to␈α
be␈α
the␈α
key␈α
problem␈α
in␈α
artificial␈α
intelligence.
␈↓ ↓H

␈↓ ↓H
␈↓ α_The␈α
results␈α
of␈α
current␈α
research␈α
in␈α
artificial␈α
intelligence␈α
is␈α
published␈α
in␈α
the␈α
journal␈α
␈↓↓Artificial
␈↓ ↓H
␈↓ ↓HIntelligence␈↓,␈α
and␈α
in␈α
more␈α
general␈α
computer␈α
science␈αpublications␈αsuch␈αas␈αthose␈αof␈αthe␈αACM␈αand␈αthe
␈↓ ↓H
␈↓ ↓HBritish␈α⊂Computer␈α⊂Society.␈α⊂The␈α⊂ACM␈α∂has␈α∂a␈α∂special␈α∂interest␈α∂group␈α∂on␈α∂artificial␈α∂intelligence␈α∂called
␈↓ ↓H
␈↓ ↓HSIGART␈α∪which␈α∪publishes␈α∪a␈α∪bulletin.␈α∩Every␈α∩two␈α∩years␈α∩there␈α∩is␈α∩an␈α∩international␈α∩conference␈α∩on
␈↓ ↓H
␈↓ ↓Hartificial␈αintelligence␈αwhich␈αpublishes␈αa␈α
proceedings.␈α
The␈α
third␈α
and␈α
most␈α
recent␈α
was␈α
held␈α
at␈α
Stanford
␈↓ ↓H
␈↓ ↓Hin␈α⊃the␈α⊃summer␈α⊂of␈α⊂1973␈α⊂and␈α⊂the␈α⊂Proceedings␈α⊂can␈α⊂be␈α⊂obtained␈α⊂from␈α⊂Stanford␈α⊂Research␈α⊂Institute,
␈↓ ↓H
␈↓ ↓HMenlo␈α
Park,␈α
Calif.␈αat␈αa␈αcost␈αof␈α$15.00.␈αSome␈αcurrent␈αbooks␈αand␈αpapers␈αare␈αlisted␈αat␈αthe␈αend␈αof␈αthis
␈↓ ↓H
␈↓ ↓Hwriteup.␈α
The␈α
Stanford␈α
Artificial␈α
Intelligence␈α
Laboratory␈α
has␈α
a␈α
series␈α
of␈α
research␈α
reports␈αwhich␈αare
␈↓ ↓H
␈↓ ↓Hincluded␈α∂in␈α∂the␈α∞reports␈α∞put␈α∞out␈α∞by␈α∞the␈α∞Computer␈α∞Science␈α∞Department.␈α∞One␈α∞can␈α∞get␈α∞on␈α∞the␈α∞list␈α∞to
␈↓ ↓H
␈↓ ↓Hreceive␈α
announcements␈α
of␈α
reports␈α
by␈α
writing␈α
them.␈α
We␈α
also␈α
have␈α
some␈α
16mm␈α
films␈α
for␈α
loan.
␈↓ ↓H

␈↓ ↓H
␈↓ α_The␈α
Stanford␈α
Artificial␈α
Intelligence␈αLaboratory␈αwas␈αstarted␈αin␈α1963␈αand␈αmoved␈αto␈αits␈αpresent
␈↓ ↓H
␈↓ ↓Hlocation␈α⊂at␈α⊂1600␈α⊂Arastradero␈α⊂Road,␈α⊂Palo␈α⊂Alto␈α⊂in␈α⊂1966.␈α⊂Since␈α⊂the␈α⊂beginning,␈α⊂our␈α⊂work␈α⊂has␈α∂been
␈↓ ↓H
␈↓ ↓Hmostly␈α∂supported␈α∂by␈α∂the␈α∂Advanced␈α∞Research␈α∞Projects␈α∞Agency␈α∞of␈α∞the␈α∞Defense␈α∞Department,␈α∞but␈α∞we
␈↓ ↓H
␈↓ ↓Hhave␈αalso␈αbeen␈αsupported␈αby␈αthe␈αNational␈αScience␈αFoundation,␈αthe␈αNational␈αAeronautics␈αand␈αSpace
␈↓ ↓H
␈↓ ↓HAgency,␈α
the␈α
National␈α
Institute␈α
of␈α
Mental␈α
Health,␈α
and␈α
private␈α
foundations.
␈↓ ↓H

␈↓ ↓H
␈↓ α_Our␈α↔research␈α↔goals␈α↔include␈α↔all␈α↔areas␈α↔of␈α↔artificial␈α↔intelligence,␈α↔mathematical␈α↔theory␈α↔of
␈↓ ↓H
␈↓ ↓Hcomputation␈α∩(the␈α∩problem␈α⊃of␈α⊃specifying␈α⊃properties␈α⊃of␈α⊃computer␈α⊃programs␈α⊃and␈α⊃proving␈α⊃that␈α⊃the
␈↓ ↓H
␈↓ ↓Hprograms␈α⊂meet␈α⊂their␈α⊂specifications),␈α⊂studies␈α⊂in␈α∂natural␈α∂language,␈α∂and␈α∂studies␈α∂in␈α∂time-sharing␈α∂and
␈↓ ↓H
␈↓ ↓Hother␈αaspects␈αof␈αcomputer␈αsystems.␈αHowever,␈αthe␈αmain␈αwork␈αof␈αthe␈αlaboratory␈αsince␈αits␈αinception␈αhas
␈↓ ↓H
␈↓ ↓Hincluded␈α
the␈α
following:
␈↓ ↓H

␈↓ ↓H
␈↓ α_1.␈α∩Computer␈α∩vision.␈α∩Images␈α∩are␈α∩obtained␈α∩from␈α∩a␈α∩television␈α∩camera␈α∩and␈α∩are␈α⊃processed␈α⊃to
␈↓ ↓H
␈↓ ↓Hdescribe␈α∩the␈α∩scene␈α∩in␈α⊃ways␈α⊃appropriate␈α⊃to␈α⊃the␈α⊃purpose␈α⊃of␈α⊃the␈α⊃program.␈α⊃These␈α⊃purpose␈α⊃include
␈↓ ↓H
␈↓ ↓Hmanipulation,␈α
driving␈α
a␈α
vehicle,␈α
and␈α
simply␈α
checking␈α
our␈α
understanding␈α
of␈α
perceptual␈α
mechanisms.
␈↓ ↓H

␈↓ ↓H
␈↓ α_2.␈α⊂Manipulation.␈α⊂Programs␈α⊂have␈α∂been␈α∂and␈α∂are␈α∂being␈α∂developed␈α∂to␈α∂assemble␈α∂objects␈α∂out␈α∂of
␈↓ ↓H
␈↓ ↓Hparts.␈α
A␈α
recent␈α
program␈α
assembles␈α
the␈α
water␈α
pump␈α
from␈α
a␈α
Model␈α
T␈α
Ford.
␈↓ ↓H

␈↓ ↓H
␈↓ α_3.␈α
Driving␈α
a␈α
vehicle.
␈↓ ↓H

␈↓ ↓H
␈↓ α_4.␈α∀Theorem␈α∀proving.␈α∀Programs␈α∀using␈α∀J.␈α∀Alan␈α∀Robinson's␈α∀resolution␈α∪method␈α∪of␈α∪proving
␈↓ ↓H
␈↓ ↓Htheorems␈α⊂in␈α⊂first␈α⊂order␈α⊂logic␈α⊂are␈α⊂used␈α⊂to␈α⊂prove␈α⊂theorems␈α⊂in␈α∂mathematics,␈α∂to␈α∂prove␈α∂properties␈α∂of
␈↓ ↓H
␈↓ ↓Hcomputer␈α
programs,␈α
and␈α
to␈α
generate␈α
computer␈α
programs␈α
having␈α
prescribed␈α
properties.
␈↓ ↓H

␈↓ ↓H
␈↓ α_5.␈α∩Mathematical␈α∩theory␈α∩of␈α∩computation.␈α∩Methods␈α∩for␈α∩proving␈α⊃properties␈α⊃of␈α⊃programs␈α⊃are
␈↓ ↓H
␈↓ ↓Hdeveloped.␈α∞Programs␈α∞for␈α∞checking␈α∞proofs␈α∞in␈α∞first␈α∞order␈α∞logic␈α∞and␈α∞in␈α∞a␈α
special␈α
logic␈α
of␈α
computable
␈↓ ↓H
␈↓ ↓Hfunctions␈α
have␈α
been␈α
developed.
␈↓ ↓H

␈↓ ↓H
␈↓ α_6.␈αGame␈αplaying.␈αSome␈αwork␈αin␈α
checkers,␈α
chess␈α
and␈α
go␈α
has␈α
been␈α
done,␈α
but␈α
we␈α
are␈α
not␈α
active␈α
in
␈↓ ↓H
␈↓ ↓Hthis␈α
field␈α
at␈α
present.
␈↓ ↓H

␈↓ ↓H
␈↓ α_7.␈α
Speech␈α
recognition.
␈↓ ↓H

␈↓ ↓H
␈↓ α_8.␈α
Computer␈α
graphics.␈αPrograms␈αhave␈αbeen␈αwritten␈αto␈αallow␈αa␈αcomputer␈αdesigner␈αto␈αput␈αlogic
␈↓ ↓H
␈↓ ↓Hdiagrams␈α⊂in␈α⊂the␈α⊂computer␈α⊂and␈α⊂diagrams␈α⊂for␈α⊂printed␈α⊂circuit␈α∂boards.␈α∂An␈α∂integrated␈α∂system␈α∂checks
␈↓ ↓H
␈↓ ↓Hconsistency␈αof␈αthe␈αvarious␈αdiagrams,␈αpermits␈αchanges␈αto␈αbe␈αmade␈αeasily,␈αand␈αproduces␈αoutput␈αfor␈α
the
␈↓ ↓H
␈↓ ↓Hautomatic␈α
manufacture␈α
of␈α
printed␈α
circuit␈α
boards␈α
and␈α
for␈α
automatic␈α
wire␈α
wrapping␈α
machines.
␈↓ ↓H

␈↓ ↓H
␈↓ α_A␈αseparate␈αproject␈αallows␈αthe␈αdesign␈αof␈αthree␈αdimensional␈αobjects␈αand␈αtheir␈αdisplay␈αin␈αvarious
␈↓ ↓H
␈↓ ↓Hviews,␈α
and␈α
the␈α
simulation␈α
of␈α
their␈α
motion␈α
and␈α
operation␈α
of␈α
joints.
␈↓ ↓H

␈↓ ↓H
␈↓ α_9.␈α∃There␈α∀is␈α∀also␈α∀development␈α∀of␈α∀time-sharing␈α∀techniques␈α∀especially␈α∀for␈α∀display␈α∀oriented
␈↓ ↓H
␈↓ ↓Htime-sharing␈α
systems.
␈↓ ↓H

␈↓ ↓H


␈↓ α_The␈αcomputer␈α
facilities␈α
of␈α
the␈α
laboratory␈α
comprise␈α
PDP-10␈α
and␈α
PDP-6␈α
processors,␈α
256K␈α
words
␈↓ ↓H
␈↓ ↓Hof␈α∂core,␈α∂a␈α∂swapping␈α∂disk,␈α∂an␈α∞IBM␈α∞3330␈α∞for␈α∞file␈α∞storage,␈α∞a␈α∞six␈α∞terminal␈α∞vector␈α∞type␈α∞keyboard␈α∞and
␈↓ ↓H
␈↓ ↓Hdisplay␈αsystem␈αand␈αa␈α
60␈α
terminal␈α
raster␈α
type␈α
display␈α
system,␈α
A-D␈α
and␈α
D-A␈α
converters,␈α
a␈α
connection␈α
to
␈↓ ↓H
␈↓ ↓Hthe␈α
ARPA␈α
network,␈α
and␈α
a␈α
few␈α
external␈α
teletype␈α
speed␈α
lines.␈αConnected␈αto␈αthe␈αsystem␈αare␈αtelevision
␈↓ ↓H
␈↓ ↓Hcameras,␈α
mechanical␈α
arms,␈α
and␈α
a␈α
computer␈α
controllable␈α
cart␈α
with␈α
a␈α
TV␈α
camera.
␈↓ ↓H

␈↓ ↓H
␈↓ α_The␈α∀personnel␈α∀of␈α∀the␈α∀laboratory␈α∀include␈α∀faculty␈α∀and␈α∪students␈α∪of␈α∪the␈α∪Computer␈α∪Science
␈↓ ↓H
␈↓ ↓HDepartment␈α∞and␈α∞a␈α∞few␈α∞other␈α∞departments␈α∞at␈α∞Stanford␈α∞University,␈α∞the␈α
professional␈α
staff,␈α
and␈α
some
␈↓ ↓H
␈↓ ↓Hresearch␈αassociates.␈αPotential␈αgraduate␈αstudents␈αwishing␈αto␈αspecialize␈αin␈αartificial␈αintelligence␈αand␈αdo
␈↓ ↓H
␈↓ ↓Hresearch␈αin␈αthe␈αlaboratory␈αshould␈αusually␈αapply␈αfor␈αadmission␈αto␈αthe␈αComputer␈αScience␈αDepartment
␈↓ ↓H
␈↓ ↓Hat␈α
Stanford␈α
University.␈α
Potential␈α
research␈α
associates␈α
should␈α
apply␈α
directly␈α
to␈α
the␈α
laboratory.
␈↓ ↓H

␈↓ ↓H
␈↓ α_The␈α∀director␈α∀of␈α∀the␈α∀Laboratory␈α∀is␈α∀John␈α∀McCarthy,␈α∀professor␈α∪of␈α∪computer␈α∪science.␈α∪The
␈↓ ↓H
␈↓ ↓Hassociate␈α∞directors␈α
are␈α
Jerome␈α
Feldman,␈α
associate␈α
professor␈α
of␈α
computer␈α
science␈α
and␈α
Lester␈α
Earnest
␈↓ ↓H
␈↓ ↓Hwho␈α
is␈α
also␈α
executive␈α
officer␈α
of␈α
the␈α
laboratory.␈α
The␈α
mailing␈α
address␈α
of␈α
the␈α
laboratory␈α
is
␈↓ ↓H

␈↓ ↓H
␈↓ β8Stanford␈α
Artificial␈α
Intelligence␈α
Laboratory
␈↓ ↓H
␈↓ β8Stanford,␈α
California␈α
94305
␈↓ ↓H

␈↓ ↓H

␈↓ ↓H
␈↓β
␈↓ ↓H
References
␈↓ ↓H

␈↓ ↓H

␈↓ ↓H
[1]  Newell, Allen and Simon, Herbert A., HUMAN PROBLEM SOLVING, Prentice-Hall,
␈↓ ↓H
␈↓ α`Englewood Cliffs, New Jersey (1972).
␈↓ ↓H

␈↓ ↓H
[2]  Nilsson, Nils, PROBLEM SOLVING METHODS IN ARTIFICIAL INTELLIGENCE, 
␈↓ ↓H
␈↓ α`McGraw-Hill, Inc. (1971).
␈↓ ↓H

␈↓ ↓H
[3]  Nilsson, Nils, "Artificial Intelligence" in PROCEEDINGS IFIP CONGRESS 1974,
␈↓ ↓H
␈↓ α`Stockholm, Sweden, (1974) and also ARTIFICIAL INTELLIGENCE CENTER TECHNICAL
␈↓ ↓H
␈↓ α`NOTE #89, Stanford Research Institute, Menlo Park, California, (1974).
␈↓ ↓H

␈↓ ↓H
[4]  Slagle, James R., ARTIFICIAL INTELLIGENCE:  THE HEURISTIC-PROGRAMMING
␈↓ ↓H
␈↓ α`APPROACH, McGraw-Hill, (1971).
␈↓ ↓H

␈↓ ↓H