CREATE TABLE dataset (datasetid INT, datasetname VARCHAR)
CREATE TABLE paperfield (fieldid INT, paperid INT)
CREATE TABLE writes (paperid INT, authorid INT)
CREATE TABLE field (fieldid INT)
CREATE TABLE keyphrase (keyphraseid INT, keyphrasename VARCHAR)
CREATE TABLE journal (journalid INT, journalname VARCHAR)
CREATE TABLE cite (citingpaperid INT, citedpaperid INT)
CREATE TABLE paperdataset (paperid INT, datasetid INT)
CREATE TABLE author (authorid INT, authorname VARCHAR)
CREATE TABLE paper (paperid INT, title VARCHAR, venueid INT, year INT, numciting INT, numcitedby INT, journalid INT)
CREATE TABLE venue (venueid INT, venuename VARCHAR)
CREATE TABLE paperkeyphrase (paperid INT, keyphraseid INT)

How many papers has Richard Ladner and Linda Shapiro written together ?
SELECT DISTINCT COUNT(1) FROM author AS AUTHOR_0, author AS AUTHOR_1, writes AS WRITES_0, writes AS WRITES_1 WHERE AUTHOR_0.authorname = 'Richard Ladner' AND AUTHOR_1.authorname = 'Linda Shapiro' AND WRITES_0.authorid = AUTHOR_0.authorid AND WRITES_1.authorid = AUTHOR_1.authorid AND WRITES_1.paperid = WRITES_0.paperid
SELECT DISTINCT COUNT(1) FROM "author" AS "AUTHOR_0" JOIN "writes" AS "WRITES_0" ON "AUTHOR_0"."authorid" = "WRITES_0"."authorid" JOIN "writes" AS "WRITES_1" ON "WRITES_0"."paperid" = "WRITES_1"."paperid" JOIN "author" AS "AUTHOR_1" ON "AUTHOR_1"."authorid" = "WRITES_1"."authorid" AND "AUTHOR_1"."authorname" = 'Linda Shapiro' WHERE "AUTHOR_0"."authorname" = 'Richard Ladner'